Criticism of Wikipedia has increased with its prominence. Critics include current and former Wikipedians, representatives of other encyclopedias, and subjects of articles. Notable criticisms include that its open nature makes Wikipedia unauthoritative and unreliable, that it exhibits systemic bias, and that the group dynamics of its community hinder its goals. Others consider Wikipedia to be functioning well as an encyclopedia, particularly when used for research on uncontroversial or obscure topics.
Criticism of the concept
Usefulness as a reference
Wikipedia's utility as a reference work has been questioned. The lack of authority, accountability, and peer review are considered disqualifying factors by some. For example, librarian Philip Bradley acknowledged in an interview with The Guardian that the concept behind the site was in theory a "lovely idea," but that he would not use it in practice, and that he is "not aware of a single librarian who would. The main problem is the lack of authority. With printed publications, the publishers have to ensure that their data is reliable, as their livelihood depends on it. But with something like this, all that goes out the window" (Waldman 2004). Likewise, Robert McHenry, former editor-in-chief of Encyclopædia Britannica said: "The user who visits Wikipedia to learn about some subject, to confirm some matter of fact, is rather in the position of a visitor to a public restroom. It may be obviously dirty, so that he knows to exercise great care, or it may seem fairly clean, so that he may be lulled into a false sense of security. What he certainly does not know is who has used the facilities before him" (McHenry 2004). However, Discover Magazine noted in its March 2006 issue that "[s]cience entries in Wikipedia, the open-source online encyclopedia that anyone can edit, are nearly as error-free as those in Encyclopædia Britannica, according to a team of expert reviewers."
Suitability as an encyclopedia
Critics such as McHenry have said that Wikipedia errs in billing itself as an encyclopedia, because that word implies a level of authority and accountability that an openly editable reference work allegedly cannot possess. McHenry argues that "to the ordinary user, the turmoil and uncertainty that may lurk beneath the surface of a Wikipedia article are invisible. He or she arrives at a Wikipedia article via Google, perhaps, and sees that it is part of what claims to be an "encyclopedia". This is a word that carries a powerful connotation of reliability. The typical user doesn't know how conventional encyclopedias achieve reliability, only that they do" (McHenry 2005). Frequent Wikipedia critic Andrew Orlowski writes:
- If what we today know as 'Wikipedia' had started life as something called, let's say — 'Jimbo's Big Bag O'Trivia' — we doubt if it would be the problem it has become. Wikipedia is indeed, as its supporters claim, a phenomenal source of pop culture trivia. Maybe a 'Big Bag O'Trivia' is all Jimbo ever wanted. Maybe not.
- For sure a libel is a libel, but the outrage would have been far more muted if the Wikipedia project didn't make such grand claims for itself. The problem with this vanity exercise is one that it's largely created for itself. The public has a firm idea of what an 'encyclopedia' is, and it's a place where information can generally be trusted, or at least slightly more trusted than what a labyrinthine, mysterious bureaucracy can agree upon, and surely more trustworthy than a piece of spontaneous graffiti — and Wikipedia is a king-sized cocktail of the two. (Orlowski 2005)
Jerry Holkins of Penny Arcade noted on his online webcomic that the "response [to criticisms of Wikipedia] is: the collaborative nature of the apparatus means that the right data tends to emerge, ultimately, even if there is turmoil temporarily as dichotomous viewpoints violently intersect. To which I reply: that does not inspire confidence. In fact, it makes the whole effort even more ridiculous. What you've proposed is a kind of quantum encyclopedia, where genuine data both exists and doesn't exist depending on the precise moment I rely upon your discordant fucking mob for my information." 
Academic circles have not been entirely dismissive of Wikipedia as a source of information. Wikipedia articles have been referenced in "enhanced perspectives" provided on-line in the journal Science. The first of these perspectives to provide a hyperlink to Wikipedia was "A White Collar Protein Senses Blue Light" (Linden 2002:297 (5582)), and dozens of enhanced perspectives have provided such links since then. However, these links are offered as background sources for the reader, not as sources used by the writer, and the "enhanced perspectives" are not intended to serve as reference material themselves. Others have suggested that while Wikipedia may not be an encyclopedia, this is not such a bad thing. A discussion on MeatballWiki on the topic contains the following introduction:
- The Wikipedia is not an encyclopedia. No-one should be offended by that statement, it doesn't mean that it is less or more, it means it is different, something new. The classical encyclopedia was a compendium of knowledge in a limited amount of space, it was not an attempt to gather all knowledge, it was an attempt to compile the important knowledge, the essence of what a knowledgable person might be expected to know. The restriction to - let's say - 25 x 1000 = 25.000 pages was characteristic and important. It meant that any topic had to meet two challenges: (1) is it important enough to make an entry and (2) how much space should be devoted to it. None of these characteristics applies to the Wikipedia, so Wikipedia is something new. Maybe its a try at a new library of Alexandria containing all available knowledge. 
Anti-elitism as a weakness
Former editor-in-chief of Nupedia, Larry Sanger, stated in an opinion piece in kuro5hin that "anti-elitism" — active contempt for expertise — was rampant within the Wikipedia community. He further stated that "[f]ar too much credence and respect [is] accorded to people who in other Internet contexts would be labelled 'trolls'." A common Wikipedia maxim is "Out of mediocrity, excellence." Jimmy Wales, the site's founder, admits that wide variations in quality between different articles and topics is not insignificant, but that he considers the average quality to be "pretty good," getting better by the day. Staff at the Encyclopædia Britannica say it does not feel threatened by Wikipedia. "The premise of Wikipedia is that continuous improvement will lead to perfection; that premise is completely unproven," the reference work's executive editor, Ted Pappas, told The Guardian.
Systemic bias in coverage
Wikipedia has been accused of systemic bias, a tendency to cover topics in a detail disproportionate to their importance. Even the site's proponents admit to this unavoidable flaw. In an interview with The Guardian, Dale Hoiberg, the editor-in-chief of Encyclopædia Britannica, noted that "people write of things they're interested in, and so many subjects don't get covered; and news events get covered in great detail. The entry on Hurricane Frances is more than five times the length of that on Chinese art, and the entry on Coronation Street is twice as long as the article on Tony Blair" (Waldman 2004). Waldman gave this interview on October 26, 2004. By March 28, 2005, without counting subarticles, the Chinese art article had become three times as large as the article on Hurricane Frances, while the article on Tony Blair was 50% larger than the article on Coronation Street. Proponents of Wikipedia point to such statistics to show that systemic bias will diminish over time. Opponents point out that these articles drew attention from the Wikipedia community because they were specifically mentioned by Hoiberg, and this increase in size was not universal. While it has long been one of Jimmy Wales' goals to distribute Wikipedia in the poor nations of the world, the current Wikipedia would give them a product that does an inadequate job of covering their regions. Below is a comparison between how many times Canada and Nigeria are mentioned in four encyclopedias. The second column is the ratio of mentions of Belgium to mentions of Rwanda.
Systemic bias in perspective
A more difficult problem to address is that, even when topics are covered, they are covered from what seems to be a neutral point of view to the current participants only, which may not meet the neutrality standards of the current readership as a whole, or of the potential readership. While some critics have raised this issue within the Wikipedia community, they have been unsatisfied with the response. For example, a 2002 attempt to ask questions about what would be required to prepare Wikipedia for the one billionth user went nowhere. Since that time, there have been numerous efforts to address the difference between neutral point of view and the perspective of new contributors with views typical of some large group of people, but not typical of the average Wikipedia contributor. In response to this issue, a group of Wikipedians on the English Wikipedia have established a WikiProject, Wikipedia:WikiProject Countering systemic bias. They have a list of open tasks which detail various areas they have determined need to be resolved. The concept of a neutral point of view itself has itself been criticized as being misleading, impossible, and sometimes even offensive in its results. Some critics and even some Wikipedians say that a NPOV is an unattainable ideal, although this does not rule out the possibility of a close approximation being reached.
Difficulty of fact-checking
Wikipedia contains no formal peer review process for fact-checking, and due to the lack of requiring qualifications to edit any article, the editors themselves may not be well-versed in the topics they write about. Since the bulk of Wikipedia's fact-checking involves an internet search (which may find mirrors of Wikipedia, including some which do not clearly acknowledge their nature as such), self-perpetuating errors are inevitable. The amount of fact-checking per page is directly related to the amount of frequent editors per page, thus errors on obscure topics may remain for some time. Even in pages with dozens of editors, a fact erroneously inserted along with dozens of other changes may "slip" into a page and stay. As well, since all edits of one user are displayed instantly to all readers, it is essentially impossible for any fact checking to occur until after the information (or misinformation) is already published. This particular criticism is Wikipedia's most frequently encountered weakness in reality. Sometimes, the subject of a biographical article must fix blatant lies about his own life.  A nihilartikel was once inserted into Wikipedia that lasted for five months. One editor made five edits which remained unnoticed for up to five days .
Use of dubious sources
Wikipedia requests Wikipedians to verify the accuracy of information by checking the references cited, which generally come from external sources. Many of these articles often do not include references for statements made, nor do the articles differentiate between true, false, and opinion. Some critics contend that the references have come from dubious sources, such as blog entries. For example, a blog entry may contain several inaccuracies and stereotypes, because many bloggers may have their own self-interests. Critics contend that use of such unsound references give legitimacy to articles, which contain many falsehoods. An article about the soundness of a particular issue may find legitimacy by using references found on an organization's website supporting that particular stance. Wikipedia's policies on sourcing, however, do not allow blogs to be used as primary sources. Hiawatha Bray (2004) of the Boston Globe wrote: "So of course Wikipedia is popular. Maybe too popular. For it lacks one vital feature of the traditional encyclopedia: accountability. Old-school reference books hire expert scholars to write their articles, and employ skilled editors to check and double-check their work. Wikipedia's articles are written by anyone who fancies himself an expert.".
Exposure to vandals
In 2005, Wikipedia received a great deal of bad publicity as a result of the John Seigenthaler Sr. Wikipedia biography controversy, in which a then-unknown vandal created a biographical page on Seigenthaler containing numerous false and defamatory statements; this page went unnoticed for several months until discovered by Victor S. Johnson, Jr., a friend of Seigenthaler. Likewise, numerous other pages have been attacked and defaced by vandals; either with axes to grind against a particular subject (then defamed or unfairly and unencyclopedically criticized in a Wikipedia article); or against Wikipedia itself. There have even been instances of Wikipedia critics injecting false information into Wikipedia in order to "test" the system and demonstrate its alleged unreliability. Wikipedia itself acknowledges these issues. "Researching with Wikipedia", a "project page" (that is, part of the Wikipedia site, though not part of the encyclopedia as such), states, "Wikipedia's radical openness means that any given article may be, at any given moment, in a bad state: for example it could be in the middle of a large edit or it could have been recently vandalized. While blatant vandalism is usually easily spotted and rapidly corrected, Wikipedia is certainly more subject to subtle vandalism than a typical reference work."  Wikipedia has numerous tools available to editors (and several more available only to administrators) in order to combat vandalism; proponents of the encyclopedia argue that the vast majority of attacks on Wikipedia are detected and reverted within a short time frame (one study by IBM found that most vandalism on Wikipedia is reverted in about 5 minutes ). Notwithstanding such assurances, there have been several incidents where defamatory, unsubstantiated, or manifestly untrue claims have persisted in current versions of Wikipedia articles for significant amounts of time, the Seigenthaler incident being the most prominent such incident to date. Supporters of Wikipedia also frequently claim that undetected vandalism mainly is an issue with low-profile articles. Most undetected vandalizing edits are done by registered users, which are often reviewed less often than those by anonymous users. Scholarly sounding vandalism isn't easily detected because it is well written and fits the style of the article. If someone added a line saying that a famous person "farts all the time," it would be erased. A scholarly-sounding paragraph about flatulence existed for over a month in a Wikipedia biography:
Never the one to be embarrassed by life's peculiarities, Larry King has often been said to have a bit of a flatulence habit while on air at CNN, which isn't curbed by having guests in the studio. A favorite moment of his, and an often repeated story, involved an interview conducted with former President Jimmy Carter who, after some length of time in studio, chided Larry & asked him to please stop, or he'd have to end the interview. Larry ever present in the moment adeptly steered the conversation to global warming and the effects of bovine emissions on the ozone.
It should be noted that such postings violate numerous Wikipedia policies, most importantly Wikipedia's policy on verifiability. Additionally, the issue of vandalism detection is an important one. Most vandalism is detected via "Recent changes", a listing of all recent edits. As such, even obvious vandalism that slips by those who watch for vandalism may remain undetected for several weeks, or even months.
Exposure to political operatives and advocates
While Wikipedia has a policy requiring articles to have a neutral point of view, it is not immune from attempts by outsiders with an agenda to place a spin on articles. In January 2006 it was revealed that several staffers of members of the U.S. House of Representatives had embarked on a campaign to cleanse their respective bosses' biographies on Wikipedia, as well as inserting negative remarks on political opponents. References to a campaign promise by Martin Meehan to surrender his seat in 2000 were deleted by Meehan's staffers, and a congressional staffer inserted a comment in the article on Bill Frist claiming he is "ineffective". Some of the remarks were well outside the usual bounds of fair comment, such as a claim that Eric Cantor, a congressman from Virginia, "smells like cow dung". In an interview, Wikipedia founder Jimmy Wales remarked that the changes were "not cool". Numerous other changes were made from an IP address which is assigned to the House of Representatives.
Most privacy concerns refer to cases of government or employer data gathering; or to computer or electronic monitoring; or to trading data between organizations. See LEGAL ISSUES IN EMPLOYEE PRIVACY for example. The concern in the case of Wikipedia is the right of a private citizen to remain private; to not move from being a "private citizen" to being a "public figure" in the eyes of the law (see  for the legal distinction). It is somewhat of a battle between the right to be anonymous in cyberspace and the right be anonymous in real life (meatspace). "[T]he Internet has created conflicts between personal privacy, commercial interests and the interests of society at large" warns James Donnelly and Jenifer Haeckl in PRIVACY AND SECURITY ON THE INTERNET: What Rights, What Remedies?. Balancing the rights of all concerned as technology alters the social landscape will not be easy. It "is not yet possible to anticipate the path of the common law or governmental regulation" regarding this problem. . Daniel Brandt's Wikipedia Watch states "Wikipedia is a potential menace to anyone who values privacy. [...] A greater degree of accountability in the Wikipedia structure, as discussed above, would also be the very first step toward resolving the privacy problem." Paradoxically, Brandt's own website violates the privacy of several Wikipedia administrators by publishing their personal information without their consent.  Brandt appears to justify this (from his personal perspective) as retribution against the existence of his own Wikipedia page. A particular problem occurs in the case of an individual who is relatively unimportant and for whom there exists a Wikipedia page against their will. An argument can be sustained that if the person for example has mental health problems, the public's right to know about such an unimportant individual is easily outweighed by the detrimental effects on such an individual of the Wikipedia page. A list of such individuals will not be given here, so as to not draw further attention to them. In addition, Wikipedia has run afoul of privacy laws in countries outside the United States, where it is hosted. In January, 2006 a German court ordered the German-language Wikipedia shut down within Germany due to its publication of the full name of Boris Floricic, aka "Tron", a deceased hacker who was formerly with the Chaos Computer Club. More specifically, the court ordered that the URL within the German .de domain (http://www.wikipedia.de/) may no longer redirect to the encyclopedia's servers in Florida at http://de.wikipedia.org/, though since German readers are still able to use the US-based URL directly, there is not really any loss of access on their part. The court order arose out of a lawsuit filed by Floricic's parents, demanding that their son's surname be removed from Wikipedia.  German law provides that the media may not publish the full names of defendants in criminal proceedings. On January 20, the Wikimedia Foundation, which hosts the various Wikipedias, reached a settlement with the court in the matter.  Other countries may also have privacy laws which come into conflict with Wikipedia's editorial policies, which are heavily dependent on free speech laws in effect in the U.S., and generally permit publication of anything which is verifiable and does not contain an inappropriate point of view.
Many critics of Wikipedia – as well as many within the Wikipedia community – have observed that the quality of articles varies widely, even when controversial topics are excluded from the discussion. Some articles are excellent by any reasonable measure – authored and edited by persons knowledgeable in the field, containing numerous useful and relevant references, and written in a proper encyclopedic style. However, there are many articles on Wikipedia which are amateurish, unauthoritative, and even incorrect, making it difficult for a reader unfamiliar with the subject matter to know which articles are correct and which are not. In addition, Wikipedia contains many articles which are stubs – articles which provide a brief definition of a term, and little else. Others have noted that in some areas, such as science, Wikipedia's quality is often excellent. A report by Nature, a highly-regarded scientific journal, finds that "Wikipedia comes close to Britannica in terms of the accuracy of its science entries". The article detailed a study wherein 42 articles in both encyclopedias were reviewed by experts on the subject matter. Based on the review, the average Wikipedia article contained 4 errors or omissions; the average Britannica article, 3. Encyclopædia Britannica's initial concerns led to Nature releasing further documentation of its survey method. . Encyclopædia Britannica, in its formal corporate response "Fatally Flawed"  (March 2006), responded that "[t]hat conclusion was false, however, because Nature’s research was invalid. As we demonstrate below, almost everything about the journal’s investigation, from the criteria for identifying inaccuracies to the discrepancy between the article text and its headline, was wrong and misleading." However, Britannica also spun their mistakes:
- Article: Mendeleev, Dmitry ["Medeleyev, Dmitry Ivanovich"]
- Reviewer comment: Declaring him the 17th child is either incorrect or misleading. He is the 13th surviving child of 17 total.
- Britannica responds: We disagree with the reviewer's implications that there is full agreement that Mendeleev was the 13th surviving child. Our new article makes it clear that scholars are not uniform in their views on whether Mendeleyev was the 13th or 14th surviving child. (source)
According to a BBC report , Nature has since rejected the Britannica response. ()
Threat to traditional publishers
Some observers claim that Wikipedia is undesirable, because it is an economic threat to publishers of traditional encyclopedias, many of whom may be unable to compete with a product which is essentially free. Nicholas Carr writes in the essay The amorality of Web 2.0, speaking of the so-called Web 2.0 as a whole:
- Wikipedia might be a pale shadow of the Britannica, but because it's created by amateurs rather than professionals, it's free. And free trumps quality all the time. So what happens to those poor saps who write encyclopedias for a living? They wither and die. The same thing happens when blogs and other free on-line content go up against old-fashioned newspapers and magazines. Of course the mainstream media sees the blogosphere as a competitor. It is a competitor. And, given the economics of the competition, it may well turn out to be a superior competitor. The layoffs we've recently seen at major newspapers may just be the beginning, and those layoffs should be cause not for self-satisfied snickering but for despair. Implicit in the ecstatic visions of Web 2.0 is the hegemony of the amateur. I for one can't imagine anything more frightening.
Others dispute the notion that Wikipedia, or similar efforts, will entirely displace traditional publications.
Wikipedia has been criticized by many for allowing users to edit anonymously, with only their IP address to identify them. This is said to allow the vandals anonymity and makes it difficult to track them, due to the long and hard to remember nature of IP addresses. However IP edits reveal their IP address which can be used by admins to complain to ISPs or put range blocks in place or not to block because of possible blocking of regular editors who share the same IP. Many have suggested making user registration required to edit articles, and as of December 6, 2005 only registered users can create pages (Wales 2005). The vast majority of vandalism on Wikipedia is done by anonymous users. Of course, many anonymous users make good edits. Vandalism is still relatively straightforward to deal with. Due to the many users of Wikipedia, most vandalism is reverted quickly. It is predicted that as the number of Internet users grows, the interest in Wikipedia will grow immensely. With this immense growth, critics of anonymous editing predict, will come a hard to cope with amount of vandalism as more and more people discover Wikipedia. However exponential growth will also increase the number of non vandal editors who are able to revert vandal edits.
A significant number of people have commented that many images, and some articles, are copyright violations. Often images are uploaded and incorrectly tagged as fair use, which is discouraged but not disallowed on Wikipedia. However, unless an image has a fair use criteria, it will likely be listed on images for deletion. There is also a copyright violations page where violations can be listed, and Wikipedia has their own designated agent who can take down content when requested.
Criticism is also targeted at the community of Wikipedia editors, whose group dynamics manifest themselves in how and by whom articles are edited. Critics of these processes argue that they are actively hindering the production of a quality encyclopedia.
Some people predict that Wikipedia is going to end up as "just a bunch of flame wars". This concern has been acknowledged by Wikipedia's community, which has developed a concept of "Wikiquette" in response.
Fanatics and special interests
Several contributors have complained that editing Wikipedia is very tedious in the case of conflicts and that sufficiently dedicated contributors with idiosyncratic beliefs can push their point of view, because nobody has the time and energy to counteract the bias. Some contributors have alleged that informal Wikipedia coalitions work regularly to push and to suppress certain points of view. For example, they often allege that certain pages have been taken over by fanatics and special interest groups that consistently revert the contributions of new contributors. This problem tends to occur most around controversial subjects, and sometimes results in revert wars and pages being locked down. In response, an Arbitration Committee has been formed on the English Wikipedia that deals with the worst offenders — though a conflict resolution strategy is actively encouraged before going to this extent. Also, to stop the continuous reverting of pages, Jimmy Wales introduced a "three revert rule", whereby those users who revert an article more than three times in a 24 hour period are blocked for 24 hours.
Some argue that criticisms and commentary on certain topics are systematically excluded, deleted or reverted by self-appointed censors, and that even attempts to make compromises or build up articles to include a variety of views are thwarted by uncompromising "vandal-editors" who simply delete or revert unwanted views that don't fit their agenda. Wikipedia's policy is to fairly represent all sides of a dispute by not making articles state, imply, or insinuate that only one side is correct; however it can be difficult for this policy to be enforced.  The Wikimedia Foundation, parent of Wikipedia, has received substantial contributions from foundations that promote a political agenda, such as $40,000 from the Lounsbery Foundation of Richard Lounsbery and $20,000 from the Open Society Institute of George Soros. 
Abuse of power
A number of editors have quit after denouncing what they have described as abuses of power by Administrators and the Arbitration Committee. Such abuses include ignoring violations by Administrators and conducting Arbitration Committee actions which are in violation of the Wikipedia:Arbitration policy.
- Anotherblogispossible, May 20 2004.
- Why Wikipedia sucks. Big time, June 2 2004.
- Wikipedia Reputation and the Wemedia Project, quoting many people criticizing Wikipedia and others rebutting them. - by Ross Mayfield, August 29 2004.
- The Great Failure of Wikipedia - by Jason Scott, November 19 2004.
- Why Wikipedia Must Jettison Its Anti-Elitism - by Larry Sanger, co-founder of Wikipedia. December 30 2004.
- A Criticism of Wikipedia Now Exceeding a Scream - by Jason Scott, January 3 2005.
- Wikipedia is a real-life Hitchhiker's Guide: huge, nerdy, and imprecise - by Paul Boutin, Slate, May 3 2005.
- Swastikipedia - by Jason Scott, May 4 2005.
- Wikipedia: The Agony of Delete - by Rogers Cadenhead, August 31 2005.
- Information quality discussions in Wikipedia - by Besiki Stvilia, et al. Updated October 19 2005.
- Can you trust Wikipedia? - by Mike Barnes, The Guardian, October 24 2005.
- Wikipedia: magic, monkeys and typewriters - by Andrew Orlowski, The Register, October 24 2005.
- Can you trust Wikipedia? - by Elvira van Noort, Mail & Guardian (South Africa), November 7 2005.
- A false Wikipedia 'biography' - by John Seigenthaler Sr., USA Today, November 29 2005.
- "The Danger of Wikipedia", Editor and Publisher, November 30 2005. (Login required)
- Snared in the Web of a Wikipedia Liar - by Katharine Q. Seelye in The New York Times, December 3 2005.
- Unreliable (adj): log on and see - by Rosemary Righter, The Times, December 9 2005
- Online encyclopedias put to the test - by Stephen Cauchi, December 14 2005.
- Founded On Porn, Wikipedia Shapes The Way You Think - by Jennifer Monroe, December 15 2005.
- Wikipedia science 31% more cronky than Britannica's - by Andrew Orlowski, The Register, December 16 2005.
- "Wikipedia founder admits to serious quality problems" - by Andrew Orlowski, The Register, December 18 2005.
- Wikipedia Founder Looks Out for Number 1 - by Rogers Cadenhead, December 19 2005.
- Wikipedia, Porn and the Airbrushing of History - by Jeremy Wagstaff, December 20 2005.
- Putting Wikipedia Flap in Perspective, December 23 2005.
- Wikipedia target of House 'editors' - by Evan Lehmann, TheTranscript.com, January 30 2006.
- Profs knock Wikipedia - by Brittany Anas, February 6 2006. (Login required)
This article incorporates text from the GFDL Wikipedia article Wikipedia:Replies to common objections.