Nothing is perfect, and Wikipedia is no exception. This page enumerates user opinions on why Wikipedia is not so great. For formal criticisms, see Criticism of Wikipedia. Much of the presented criticism is debated in separate essays: "Wikipedia is succeeding", "Wikipedia is failing", "Why Wikipedia is so great", and "Replies to common objections".

The following opinions are grouped into related sets. Since 2003, problems of inaccuracy (below under: Accuracy) were considered by some as the biggest issue. However, others have felt "POV pushing" (or bias, below under: NPOVness (non-bias)) to be a bigger problem, because statements could contain accurate facts while expressing only one point of view about a subject, rather than being a balanced, impartial treatment. There have been documented problems caused by open, anonymous gatherings of people on Wikipedia, such as the writing of vitriol (noted in 2003) or wiki-gangs (noted in July 2005). Another problem is that anyone can edit articles at any time, so people can vandalize articles, as long as they have an account. Some schools have been banned from making an account and that helps a little, but people can still vandalize out of school.

• Mirrors of Wikipedia are not always swiftly updated. Misinformation which is quickly corrected on Wikipedia itself may persist for some time in the mirrors. Heck, it took me less than a minute to type this sentence up. And it's just that easy to edit. Wikipedia itself prevents any real solution to this problem by failing to encourage others to improve articles, instead demanding that Wikimedia be the cited source for any copy, even a vastly improved copy such as those that appear often at Wikinfo.
• Wiki markup is great, but it is not accessible to most users. Go to any page and click "Edit". Although help with editing is available, if you don't know how to program or if you're not previously familiar with mark-up text, it is hugely discouraging. The current support for text editors is not much better (Wikipedia:Text editor support). (The current list of proposed usability improvements includes 9 separate proposals concerning the text editor and the editing process, so this issue is not unknown in the Wikipedia community.) There may be many people out there who would like to contribute but can't, perhaps especially women – Wikipedia is dominated by male editors.

More than one thousand pages are deleted from Wikipedia each day. Most of Wikipedia's readers are unable to view its deleted articles, and numerous proposals for public access to these articles have been rejected. Many articles have been rapidly deleted via the proposed deletion and speedy deletion processes, while others have been deleted according to subjective criteria such as lack of significance or lack of notability. Sadly, these decisions are sometimes based on opinion and not research.

Wikipedia is not a democracy, and its editors may face numerous restrictions on freedom of speech, including various types of sanctions. Editors can be indefinitely blocked from Wikipedia if their usernames do not conform to Wikipedia's username policy.

• Despite claims to the opposite, Wikipedia is a bureaucracy, with increasingly complicated rules that can be edited by anyone, and a hierarchy of privileged users who enforce these rules, sometimes contradictorily. These rules have been used to delete useful information and informative images and to deface articles through over-application of bureaucratic processes. Debates and deletion discussions, as part of the bureaucratic process, divert individuals from editing and improving articles.

• People raise endless objections on Talk pages, instead of fixing what bothers them. On the other hand, people can be too bold in updating pages instead of discussing changes on Talk first. It's impossible to tell in advance how contentious something is because there's no serious indication other than an edit summary and the relative frequency of recent page edits.
• The self-esteem of a bad writer with a fragile ego may be damaged by people always correcting horrible prose, redundancies, bad grammar and spelling. This is especially true if proofreaders not only correct but upbraid the poor writers, who can perhaps offer expert knowledge or change subjective statements despite their mediocre use of English. That unnecessary discouragement repels contributors whose only fault is poor writing, not poor thinking.
• If you revert or ban too quickly, sometimes a useful contributor will be turned away. If you revert or ban too slowly, then extra time will be citing additions. Wikipedia administrator vandalism itself is controlled only weakly, and there's insufficient power to desysop a popular tyrant. Only the most abusive administrators – perhaps 2% total – have their statuses removed.
• A user can in effect exercise ownership over the topics they have the time and energy to defend. Self-appointed censors, fanatics, or other sufficiently dedicated users can further an agenda or prohibit new ideas through persistent attention to a particular page. Even listing examples of this creates problems, such as false accusations and harassment.
• People revert edits without explaining themselves (Example: an edit on Economics) (a proper explanation usually works better on the talk page than in an edit summary). Then, when somebody reverts, also without an explanation, an edit war often results. There's not enough grounding in Wikiquette to explain that reverts without comments are inconsiderate and almost never justified except for spam and simple vandalism, and even in those cases comments need to be made for tracking purposes.
• There's a culture of hostility and conflict rather than of good will and cooperation. Even experienced Wikipedians fail to assume good faith in their collaborators. It seems fighting off perceived intruders and making egotistical reversions are a higher priority than incorporating helpful collaborators into Wikipedia's community. Glaring errors and omissions are completely ignored by veteran Wikiholics (many of whom pose as scientists, for example, but have no verifiable credentials) who have nothing to contribute but egotistical reverts. There is also no acknowledgement ever that multiple communities might be using Wikipedia not by choice but because they feel they must react to changes or to people using the website.

• The very worst problem is that people think in terms of "controlling" users, and defining them as a "problem", as if there necessarily would be some judgmental view that could achieve that fairly. Would you talk about "controlling problem citizens" in a democracy? Absolutely not. Instead we closely and rigorously control words like "suspect", "criminal", "illegal" and make them meaningless and totally ineffective except in the context of a very fairly arbitrated adversarial process with a long history. There's none of that when some influential "Wikipedian" labels a person "a problem".
• That said, there are balance and bias problems introduced by lack of controls. Anonymous users with very strong opinions and a lot of time can change many articles to support their views. Aside from IP blocks and bans for the most obnoxious, there is no means of preventing this other than attention by experienced editors, who are rare. There's no hierarchy of regular, senior, topical editors to make final rulings on extremely complex matters, e.g., by forcing two with very different views to agree.
• IP range blocks can reduce participation if they are for ranges selected and assigned dynamically by IP providers, both dial-up and broadband, making Wikipedia administrator vigilantism a particular problem. It may even be impossible to protest an unjust ban using the wiki channel itself, which is very unreasonable.
• If Wikipedia follows the pattern of every other 'community forum' on the net, small groups will become powerful to the exclusion of others. Thus the priority, inherent bias and hostility issues are likely to get worse. The increasingly nebulous "troll" could be used as an excuse for excluding people from the decision making processes behind the encyclopedia. The insistence that a cabal must exist typically stems from this concern.
• Geeks run the place. Wikipedia has become more and more hierarchical in order to 'defend freedom' from 'trolling'. This despite the fact that the Internet troll article itself acknowledges the obvious subjectivity of the term, and that it's effectively a power word used to dehumanize others. There are administrators who can delete articles. There are no checks or balances on this power built into the system, other than the attention contributors have time to give, whereas their ability to delete and ban is built in at the coding level. Administrators can seriously damage the site if their account is broken into, e.g., by history merges.
• Editors have learned that formation into "gangs" is the most effective way of imposing their views on opposite-minded contributors. It makes a travesty of the revert-rule when one individual can simply send an e-mail alert to friends requesting a timely "revert favour" once they have reached the limit of their daily reverts. This may apply to deletion debates as well, where a group of editors may be organised so as to always vote en masse in favour of keeping an article written by one of the gang, or related to the gang's main field of interest; or to push through deletion if their interest is a deletionism. Gangs sometimes do serious damage to Wikipedia's policies and guidelines also; by ganging up they can be written to say almost anything.

• This site is creating large numbers of wikipediholics who could be doing something more useful. Calling them addicts or cultists might not be entirely incorrect.
• Authors cannot claim authorship of any article. This makes it hard to use even the authorship of astonishingly good articles as a credential, in part because they may change before anyone looks.
• Those disaffected with humanity are provided with an outlet for their vitriol, rather than having to become misanthropes, terrorists or political researchers. Some people will take great pleasure in demonstrating the idiotic futility of such garbage. This seems like a positive quality of Wikipedia, until one realizes that any sufficiently toxic or stupid view will quickly acquire more adherents, and that defenders of a particular view tend to create factions which might soon exist offline. Any group perceiving itself as beleaguered or disadvantaged will band together more readily, and achieve common cause more readily.
• Instead of just stating the facts, many authors feel the need to attack their own pet peeves of the article's subject. They adopt pedantic tones as they correct "common belief" or a "false assumption", when facts alone are sufficient.
• The fact that any editor can edit any article regardless of competence in the subject matter may imperil the quality of articles on highly technical subjects. In case a dispute over the content of such an article ensues, an editor without specific competence can easily reorganize the content of the article based on faulty understanding of the subject.
• Deletion reviews rely on users making reasonable decisions for Wikipedia. In practice people treat the reviews as popularity contests for the article rather than attempting to follow policy (hence articles like fuck which are essentially dictionary articles). In theory the admins should fix this by checking the policy arguments, but in practice they usually count votes.

• This is the single largest problem about Wikipedia (or is POV pushing bigger?). And, in passing what does "POV" mean; this very entry fails to explain. And what does "pushing bigger" mean in international English? In itself this is a perfect of "Wikipedia Speak" which nobody except a Wikipedia obsessive can understand.
• Anyone can add subtle nonsense or erroneous information to articles that can take weeks, months or years to be detected and removed (which has been happening since at least 2002). Deliberate hoaxes can also be perpetrated.
• Even unregistered users are capable of this. For example, someone can just come and edit this very page and put in "pens are for cats only" or add mention of some unrelated topic: like how great pineapple pizza is.
• Dross can proliferate, rather than become refined, as rhapsodic authors have their articles revised by ignorant editors.

Of course, the upside of Wikipedia is that it is an encyclopedia ANYONE can edit. But the downside is that it is an encyclopedia ANYONE can edit. So, if someone wanted to, they could edit Abraham Lincoln's page to say he was a professional wrestler. For this reason, Wikipedia should be treated with caution as a research source.

• Wikipedia contains an abundance of articles which are merely a line or two long, and people simply attach {{stub}} instead of finding information to add to the topic. Editors who find stubs are often not experts in the subject but want to learn more. Consequently, if they do actually add any content, it might lack in quality.
• Anyone can remove huge amounts of text from articles or even the entire article itself, ruining lots of work. This is referred to as "blanking" by those in the Wikipedia community, and is considered vandalism. Such "blanking" is typically fixed (by reverting to the previous version of the page, before the text was removed), within minutes. However, within those few minutes, or in the few cases where such blanking is first noticed by a viewer who is not aware of the history feature of Wikipedia pages, a page may seem to be severely lacking information, or be otherwise incomplete, due to this removal.
• Anyone can insert huge amounts of text into an article, destroying readability and all sense of proportion. Attempts to redress this are often futile and occasionally result in warnings, due to the inherent bias in the Wikipedia community that bigger is somehow better.

While some have expressed a concern for "data hoarding", others have pointed out that Wikipedia has access to a large amount of server space and is not bounded by the traditional constraints of a size-limited physical encyclopedia. The general prohibition on certain subjects or levels of detail has caused some to migrate to other wiki-communities.

Although many articles in newspapers have concentrated on minor – indeed trivial – factual errors in Wikipedia articles, there are also concerns about large scale, presumably unintentional effects from the increasing influence and use of Wikipedia as a research tool at all levels. In an article in the Times Higher Education magazine (London), the radical philosopher Martin Cohen accused Wikipedia of having "become a monopoly" with "all the prejudices and ignorance of its creators imposed too". Cohen cites the examples of the Wikipedia entries on Maoism (which he implies is unfairly characterised as simply the use of violence to impose political ends) and Socrates, who (on Wikipedia at least) is "Plato's teacher who left behind not very many writings", which to readers of the Times Higher Education at least, is patent nonsense.

The example of Socrates is offered to illustrate the shallow knowledge base of editors who may then proceed to make sweeping judgements. There are many instances which have been discussed both within and outside Wikipedia of the supposed 'Western', 'white' bias of the encyclopedia, for example the assertion that 'philosophy' as an activity is essentially a European invention and discovery. Cohen accuses Wikipedia's editors of having a 'youthful cab-drivers' perspective, by which he means they are strongly opinionated and lack the tools of serious researchers to adopt a more objective standpoint.

For modern (for example, post 2000), nearly every episode of several television shows have articles. While premieres and finales may be deserving, there is little to no reason for every episode to have its own entry while the other shows do not have any information at all. And that is why Wikipedia is not so great: because a huge amount of space is devoted to meaningless articles maintained by control freaks.

This problem has been addressed by the proposed deletion and speedy deletion processes, which allow Wikipedia administrators to delete these articles rapidly.

The issue of text neutrality (or "NPOVness") involves several concerns about the content of Wikipedia and the choice of articles that are created:

• The possibility of a neutral point of view – a "view from nowhere" – can be questioned on philosophical grounds. And even if such a neutral point of view is achievable in principle, in practice it is often hard to find consensus on what views count as neutral.
• No article is actually written from a neutral point of view. Which facts about a topic are worth mentioning, and the manner and degree of detail in which they should be presented, are questions decided by the interests of the authors.
• Even the idea that a NPOV is achievable is in itself a POV. Cory Doctorow (in a response to other criticisms by Jaron Lanier) emphasized the value of transparent history: "being able to see multiple versions of [any issue], organized with argument and counter-argument, will do a better job of equipping you to figure out which truth suits you best." But this doesn't help the casual reader and certainly would not help one equipped with only a static CD or print version in some future third-world village. Doctorow acknowledges: True, reading Wikipedia is a media literacy exercise. You need to acquire new skill-sets to parse out the palimpsest. He argues it's fun, but he writes for a living and studies these things.
• Political topics can end up looking like CNN's Crossfire rather than an encyclopedia article, with point-counterpoint in every sentence when a neutral statement of fact would do better. (e.g., Bill Clinton did this good thing but some say it was bad. He also did this bad thing but some say it was not so bad as opposed to Bill Clinton did this thing and then that thing.) To put it another way, good writing makes NPOV flow like an encyclopedia; not-so-good writing makes it flow like "Crossfire". But even given that peer review will improve the standard over time, are there really enough good writers with enough time involved in Wikipedia to mitigate this weakness? Extremists tend to dominate and polarize discourse on politics, economics and any other inherently contentious field.
• A corollary is that only the most contentious topics or aspects of a topic draw enough attention to really improve. Doctorow (passim): The Britannica tells you what dead white men agreed upon, Wikipedia tells you what live Internet users are fighting over. Wikipedia is indeed inherently contentious, which makes it a good real time strategy game, but is it a good encyclopedia? Doctorow says: "Wikipedia entries are nothing but the emergent effect of all the angry thrashing going on below the surface ... if you want to really navigate the truth via Wikipedia, you have to dig into those ‘history’ and ‘discuss’ pages hanging off of every entry. That's where the real action is, the tidily organized palimpsest of the flamewar that lurks beneath any definition of ‘truth’". But while conflict theory and market-based methods assume that editorial imbalance and editorial biases are most effectively limited by adversarial process, this may simply not be true. Some independent research (by the Thomas J. Watson Research Center labs) did seem to indicate that the very best articles resulted from extremist attention and attempts to moderate it, e.g., evolution, abortion, capitalism, Islam. This may also be true of articles about politicians. But only a tiny number of the articles ever become the subject of a troll war or even more than a limited edit war. So if an adversarial process is required, most articles just aren't getting it.
• NPOV is a syntactic, not semantic, protection (concerned only with how things are stated, contrary to popular belief among Wikipedia editors it doesn't determine how well or fairly or evenly things are presented) and ideologically refusing to offer more than ArbCom, is an editorial cop-out quite possibly imposed by Jimmy Wales' insistence on staying in charge. One failing, as Robert McHenry argues in an article on balance and its lack at Wikipedia, is to consider the demographics of the users at all or explicitly plan the balance of the product as was proposed as far back as 2003. McHenry argues that letting chaos and Internet trolls set all the priorities isn't the way to achieve encyclopedic balance, and asks: In the absence of planning and some degree of central direction, how else could it have been? There are some good answers to this, notably a more regular overall governance method, but they weren't implemented. A fully qualified editorial board was never actually recruited at all, though many names were kicked around once.
• Consensus on Wikipedia may be a problematic form of knowledge production. What may appear to be a "point of view" may actually be greater knowledge and subtlety of thought than most Wikipedia users, including editors, possess. A consensus model (i.e., "What most people think" or what Wikipedia editors think is neutral) may leave us with entries defined by "Flat Worlders".
• The systemic failures mean the NPOV problem of Wikipedia is too easily seen as the fault of the person who changed the article to become problematic, rather than a systematic fault of Wikipedia. It is an unfair double standard to attribute Wikipedia's strong points to Wikipedia itself, but its weaknesses to those responsible for the problems. This is however a familiar theme – in cults. There are in fact some definitions of a "Wikipedia cultist" which echo some of the published criticisms.
• A new Internet user coming to Wikipedia for the first time (often through a link directly to the article via a general web search) will not know that articles are supposed to be NPOV and that if they detect these parts they can and should rewrite them. Doctorow says, The important thing about systems isn't how they work, it's how they fail. Fixing a Wikipedia article is simple. But that is fixing only the article. Fixing the process that fails to alert the reader to the fact they can (or might have to) fix the article, gets no attention at all. It's just left as consequence of various technical decisions. There's almost no effort to orient or train new users, and certainly none to deliberately recruit communities of under-represented people (to the balance concern above).
• Many users reflexively defend their text when possible POV is pointed out rather than reflexively making a zealous attempt to strip POV from their text instead.
• If text is perceived as POV, then it doesn't reflect well on Wikipedia. This term means "bad", but it is used in a pretty much random way. In reality there are three steps to seeing large amounts of your contributions removed by faster (not "better") editors:
  1. Someone will say "this is POV" and change it to say nothing at all, or the opposite of what it said.
  2. When you restore it, even in mediated form, it will be demanded that you provide more sources or citations, even on pages that have almost none, or in fields in which very few references publish in the conventional way – abusive and selective requirements to defend claims are all over the place.
  3. Finally, you will be labelled an Internet troll for failing to comply with these demands, and the so-called "Wikipedia:community ban" (a form of lynching) will be imposed to ensure no view seriously challenging that of the majority will ever manage to "stick" on Wikipedia pages. Even if it's correct. Especially if it's correct! Truth is not the criterion for inclusion in Wikipedia.
• Because there's no way to split irreconcilable POVs, unlike Wikinfo, you might have to work with people who believe the polar opposite to you on a given subject, and their opinion might win the day for reasons other than being correct. For example, a monomaniac, no matter how ignorant or even malicious, may "win out" eventually, because non-monomaniacs have other things to do than argue with them.
• Alternately, you might not have to work with anyone who believes the opposite to you. The stability of an article is relative to the people who are paying attention to it. Especially for less visited articles, these are not representative of all relevant POVs. Thus, often you will establish consensus for something which is still horribly POV. For instance articles on small indie bands will inevitably praise the band, because few who dislike their music are even remotely interested in their article. And, since the risk of being called an Internet troll is high, even those who do are going to be outnumbered, and possibly abused.
• Many people with causes come here to "get the word out" because publishers laugh at their stuff and site hosting costs money. So we get detailed articles about obscure activists, while the opposing establishment figures get stubs whose content is a litany of all the evil things they've done to the obscure activists, e.g., Goldman Sachs or Merrill Lynch vs Accounting scandals of 2002.
• Many people with national or ethnic heroes come here to "get the word out" as well, meaning the importance of the contributions of an individual to a particular field of endeavour can tend to be overstated (even grossly overstated) because of their belonging to a particular nation or ethnic group.
• Most, if not all, contributors have a political bias, even if they pretend not to or think they don't. Effectively, they are all working to subvert articles one way or another, as politics defies NPOV. Yet attempts to define Wikipedia:political disputes continue to fail in part because people who pretend to be "not political" claim it's just an editorial problem, not a real world issue creeping in. They even refuse to recognize Wikipedia:identity disputes as a distinct type of problem, which is more or less insane. If one group happens to have more resources, i.e., time, than other contributors, their views will prevail. Of all the so-called problems of Wikipedia this one however is least problematic: just invite their opponents who have a stake in correcting it, as Wikipedia is a big visible reference that's hard to ignore.
• Articles tend to be whatever-centric. People point out whatever is exceptional about their home province, tiny town or bizarre hobby, without noting frankly that their home province is completely unremarkable, their tiny town is not really all that special or that their bizarre hobby is, in fact, bizarre. In other words, articles tend to a sympathetic point of view on all obscure topics or places.
• Ideas to which most people related to new technologies are hostile (for example, arguments in favor of digital rights management) get reverted without thought even if written to NPOV. This is part of the systemic bias problem, as open content editors oppose DRM ideologically – an excellent example of how treatment of a Wikipedia:political dispute ought to be different than other editorial disputes.
• Wikipedia is hostile to whole fields of inquiry, as when there is controversy between "hard" scientists and scholars in any other field, Wikipedia will favor the scientists. In part due to rules on citation and what constitutes a "journal". This very readily leads to scientism, as articles rarely address epistemological differences between the ways various sciences experiment and disprove claims. Even within "hard" science, the relative certainty of something like the atomic weight of gases (easy to verify by experiment in any lab) and the absolute potential bogosity of a new physical particle (verifiable only at vast expense in equipment that costs many billions each), is never addressed. Though a few articles like infrastructure bias do explain that issue, use of terms like "universe" or "cosmology" for instance will strongly favour astronomers' views.
• Users can avoid POV criticism by cherry-picking NPOV details of an issue. By neglecting certain facts and presenting others, a series of NPOV statements as a whole may compose a very POV picture. As most Wikipedians miss the forest for the trees, such POV problems are rarely identified. And any attempt to systematically point that out, for instance, to remove anarchism, militarism, economism, scientism, legalism, or consumerism, is just as "systematically" squashed by those who share one or more of those biases themselves.

• The writing quality of some articles is sadly lacking. In such an article, paragraphs lack any cohesion and trail off without conclusions. Entire sections are composed of orphan sentences, created by piece-meal additions from random users. Similarly formed are the monstrous super-sentences, whose loose multi-layer clauses require the utmost concentration to comprehend. Users whimsically write equation-sentences ("The event is what caused excitement in the scientific community" instead of "the event excited scientists"), knowing nothing of conciseness. Punctuation and spelling are very good, but style and clarity are ignored. Wikipedians embrace bad "correct" writing, recognizing its faults only when told (or not). Use of passive tense actually seems to be encouraged in an effort to be boring, even when active past tense would be far better. And direct quotes are also sometimes discouraged even when they are entirely appropriate or necessary to the article's claims, or where paraphrasing would be almost certainly misconstrued.
• Many Wikipedians write in a way that is considered acceptable within the author's peer group, but is less comprehensible to the general reader. This may include the use of jargon. There's currently no systemic effort to remove it.
• In a related problem, large articles constructed via numerous (individually reasonable) edits to a small article can look okay "close up", but are often horribly unstructured, bloated, excessively "factoid", uncohesive and self-indulgent when read through completely. In short, adding a sentence at a time doesn't encourage quality on a larger scale; at some stage, the article must be restructured. This happens nowhere near often enough. Users who try to do this inevitably encounter hostility or resistance, until they figure out that they should do it with a throwaway pseudonym, not a real username.
• Wikipedia articles have a somewhat haphazard usage of American, Australian, British, Canadian, etc., as well as spelling and usage variations of the English language. There is also use of non-English words and names when English equivalents exist. See Manual of Style.

• Translations will always lag behind edits in other languages, meaning those who read Wikipedia in different languages might get different versions of the facts. Some never get English versions.
• Geek style of language. In languages other than English, a computer geek or a geekish person is often unable to express themself in a fluent written standard language, and prefers a heavily English-influenced, colloquial and unpolished geek jargon. This sort of language is often unreadable or aesthetically very displeasing to anyone who reads mainstream literature and press, and makes a singularly unprofessional impression. Besides, it roundly and soundly defeats the very reason why there should be an encyclopedia at all, i.e., providing scientific information and learning for the general public in an accessible language. The fact that writing well is a professional, or semi-professional, skill which has to be particularly learned and acquired is not nearly clear to all Wikipedians. Also, in small-language Wikipedias, the "anti-elitism" of the Wikipedia project too often translates into downright amateurishness.
• In other-language Wikipedias written in endangered, small languages, the linguistic quality of articles can be severely compromised when well-meaning enthusiasts with very limited proficiency in the language try to contribute by writing new articles or tampering with existing articles. Such people can be unable to write a grammatical sentence in the language or even be so linguistically naive they don't understand why it is so important to write grammatically. Their contributions can even drive away more proficient speakers from joining the community. In fact, the self-correcting nature of the project is turned upside down in such Wikipedias, when tamperers attack perfectly fine articles and try to add snippets of information that are already included in the article, but which the tamperer is not able to spot, because they simply aren't proficient enough in the language to understand the article (cf. the edit history of the article about Winston Churchill in the Irish-language Wikipedia). Currently, the problem is very acute in the Irish-language Wikipedia, which has a very bad press among the larger Irish-speaking community. In fact, the project seems to depend on only one person for grammatical accuracy.
• The fact that Wikipedia has so many language editions creates various Wikipedia language communities, and each active Wikipedia has its unique feature, but affects the problem that the facts presented in different language editions might be conflicting. Users who read different language editions might be perplexed.
• Different language editions of Wikipedia often have different templates and functions, resulting in the fact that sidebars, templates, infoboxes, charts and tables often can't be included in the translated article, because of calls to non-existent functions or templates that will cause error messages. Subsequently, translated articles often lack interactive maps, tables or even support for writing systems and pictures that the original did have.

• Despite being a quite huge online encyclopaedia, Wikipedia still lacks plenty of crucial articles, e.g. theoretical geography, administrative neutrality, Swedish nationalism & ColorMatch RGB.
• Popular topics (like abortion) get written about inordinately, whereas less popular ones may never receive much attention, or are hard to find.
• Geek priorities. There are many long and well-written articles on obscure characters in science fiction/fantasy and very specialised issues in computer science, physics and mathematics. Other topic areas are less active.
• Systemic bias in a particular field. For example, the overall quality of inorganic and organic chemistry articles is much better than that of physical chemistry articles.
• Absence of concrete examples in the mathematical explanations make them impenetrable to non-mathies.
• Much nonsense is added, and though it's often quickly reverted, it remains in page history making diffs impossible. For example, "Mommy Tulips live in the Philippine Islands. Many baby tulips sprout from her. For more information, please e-mail us at [email here]." What's that about? Not enough of it goes to Bad Jokes and Other Deleted Nonsense, which has now been semi-deleted anyway.
• Different viewpoints tend to create their own closed topologies of pages, and interlinking and comparison can be poor. This is exacerbated by the different camps tending to use different terminology (indeed, it is probably why they do). There's not enough effort to spot pages that must be merged, and sometimes inappropriate merges confuse general with specific abstractions too much.
• In many topics, a lot of content is there, but it's not well linked together. New users simply do not understand that articles are supposed to be heavily inter-linked and almost everything is already defined.
• Many users will associate accreditation and cite Wikipedia as a reference. Many institutions will not accept this as certified fact.
• Similarly, it can sometimes be very difficult to collect information as one may become lost in a quagmire of subtly different entries. Some of which are wholly biased but due to factional efforts have become the central article, e.g., the constant effort to redirect Islamist to Islamism which is like redirecting scientist to scientism. The more balanced articles, like Islam as a political movement, are routed around wherever possible to increase exposure of the fanatics.
• Articles become longer much more quickly than they become better. Wikipedia's strong community bias against deletion of text encourages the accretion of many authors' partial (or mis-) understandings of a topic while making it difficult for a rewriter or editor to synthesize them briefly without causing offense. There seems to be a distrust of subject matter experts, as alleged in a 2005 article by project co-founder Larry Sanger who calls it anti-elitism. He also criticizes the project's epistemic collectivism and claims it has been taken over by trolls. Which may be true, but as per above it seems almost inevitable, as trolls created it in the first place by picking contentious topics to fight over (Sanger and Wales could reasonably be seen as just the first two such trolls, to judge by their heated exchanges now).
• Non-sensical articles. Wikipedia has a large number of articles which could be considered rather irrelevant for something billing itself as an encyclopedia, such as "teh" (a misspelling of the word "the"), List of films that most frequently use the word "fuck", Goatse (an Internet shock site), Toilets in Japan, and The Flowers of Romance (British band) (a band that never played live or recorded any material).
• Infiltration by soapbox-seeking extremists, racists and the like remain a problem. This may not apply to the English-language Wikipedia with its large user community, but again, Wikipedias in smaller languages are very vulnerable to takeover attempts by extremist boarding-parties. Besides, the "geek priorities" problem is seen even here: impractical, misanthropist and extremist political views are extraordinarily common among unsociable geeks. Radical Leftist, Crypto-fascist, neo-Marxist, white supremacist, afro-centrist, racist, racialist, Islamist, and white nationalist organizations (among many others) trying to infiltrate mainstream politics often use Wikipedia as a way to introduce themselves to a wider public on their own terms.
• Articles about controversial Internet personalities or reality television celebrities might end up deleted due to widespread grudges among Wikipedians against such persons, even though they fulfilled any reasonable notability criteria.
• The same applies to articles about controversial themes. Articles like "Bronze Soldier of Tallinn" and the issue of displaying prophet Muhammad's pictures have been known to ignite flamewars.

Justice for Iran has reported that Iranian government may be interfering in Farsi Wikipedia.

• The inconsistent nature of Wikipedia and its wide variety of audiences and members makes it so that fairness and equal evaluation cannot be easily maintained. Certain articles will remain in favour of others that are identical in terms of quality, merely because those who evaluate the latter do not like the article, or have a different perspective on the article being evaluated.
• Articles are sometimes plagiarised from other sources, infringing on (international) copyright, particularly when no credit is given. The Wikipedia:Copyright problems process catches only a fraction of these.
• Images are a particularly bad case, as it is difficult to spot plagiarism when the uploader lies, but the pedantry and bureaucracy of the tagging scheme leads to other usable and useful images being deleted and removed.
• Edits by scholars and experts who disagree with some of its core values are repelled. This creates a very significant bias problem. Not least in articles about Why Wikipedia is not so great which by no means reflect all the Wikipedia:Criticisms that qualified people have levied on it.
• Similarly, fanatical or ignorant users adhering to generally good rules to Wikipedia:avoid self-references and Wikipedia:Redirects have failed to recognize the few places where these are in fact absolutely necessary. Worse, they've failed to create any project to work on these core descriptions of Wikipedia:itself to better understand the project's collective view of itself. If you can't say even what all Wikipedia users have said it "is", what use is it to try to understand their goals? No possible improved process could come without consulting this data, but if genuine self-references and meta references aren't differentiated and tracked better, it can't be easily consulted. See m:governance for an example of a process that might be so applied.
• Because Wikipedia is widely used, often showing up high in Google searches, and its dangers are not well understood by many people, misinformation in Wikipedia articles can easily spread to other external sources. In turn, the external source (which may not have cited the Wikipedia article) may be used as justification for the misinformation in future revisions of the Wikipedia article. This is sometimes called an echo chamber or "citogenesis", and some well-known Wikipedians including Wales have done it.
• Wikipedia, especially as it is propagated widely, presents an ideal target for smear campaigns and vicious rumors against individuals. While such smears can be found and edited, the rumors sometimes continue to exist in page histories, on Wikipedia mirror sites and in web-caches.
• Editing Wikipedia is tedious in the case of conflicts. There is no assistance to users caught in it, which is terrible for newbies.
• Personal preference as well as just pure meanheartedness often outrule any sense of right and wrong. Admins are not immune to this either.
• If a user is blocked indefinitely, their block log says "an expiry time of indefinite", which is a very unsensible sentence. Similarly, when they try to edit a page, it says "your block will expire indefinite".
• The charge of vandalism is broadly applied to useful edits which might oppose the view of other editors. "Vandalism" is to Wikipedia as "Witchcraft" is to Salem, or "Communism" is to McCarthy; the term is levied about too broadly.
• The "Arguments to avoid" seem to cover every possible argument. As this also eliminates simply voting, users do not have a voice unless they can come up with an argument that is not instantly rejected.
• The overly strict fair use policies and guidelines, i.e., Wikipedia:Non-free content, Wikipedia:Non-free content criteria and Wikipedia:Non-free use rationale guideline, prohibit the exhibition of fair-use images on user pages, even if the user's intention is to list all the fair-use images they have uploaded to English Wikipedia. Also, they strongly encourage users to use Linux free-software screenshots instead of Windows proprietary software ones, thus causing many software genre articles, such as raster graphics editor, unable to contain Windows proprietary software screenshots, e.g., Microsoft Paint or Adobe Photoshop, which are far more familiar to most readers than Linux free software, e.g., KolourPaint or GIMP, and cause confusion to them.
• Wikipedia editors use fashionable jargon instead of meaningful language: even on this page the neologism systemic is used when more often than not systematic is meant.

• The general problem of data hoarding has cluttered Wikipedia for many years, despite guidelines to write summary-style "encyclopedic" text backed by sources. Due to the immense scope of topics (with many pages deleted per day), it is difficult to deter data hoarding, such as sports or music articles which list dozens of scores, chart ranks, or other statistics, rather than just note the top-ten numbers and then link to sports record books or music-chart websites.
• Information of genuine editorial value, such as how often any given link is clicked from one article to another, is never made available, to help correct the cohesion of related articles or discover two names for the same thing (which would link to a lot of the same articles but never to each other).

• Wikipedia:WikiProject Editor Retention/Discovered reasons given for leaving Wikipedia
• Wikipedia:General disclaimer: a page that describes some of Wikipedia's key weaknesses
• Wikipedia:Why Wikipedia is so great
• Wikipedia:Wikipedia is failing
• Wikipedia:Wikipedia is succeeding