For some real-world examples of made-up Wikipedia information entering other sources, sometimes to the major embarrassment of the people who reused it without checking, see two recent articles: How pranks, hoaxes and manipulation undermine the reliability of Wikipedia
and I accidentally started a Wikipedia hoax
. It happens quite a lot, at least in the English Wikipedia, that hoaxes stay around for years before they are discovered, by which time they have entered all sorts of other sources (remember the Bicholim conflict?
). Even people who work for Wikipedia tell you not to trust it
, but to check the underlying citations.
It would help if the English Wikipedia had edits by new and unregistered users looked at and approved by more experienced Wikipedians before showing them to the public (that's how it's done in the German and Polish Wikipedias for example), but the English Wikipedia community has steadfastly refused to introduce that system ("Pending Changes", also known as "Flagged Revisions") in all of its articles, saying it would be too much work and be a downer for new contributors who might have to wait a while before they see their changes go live.
For examples of Wikipedia being abused for personal vendettas against people, see Revenge, ego and the corruption of Wikipedia
and The tale of Mr Hari and Dr Rose:
A false and malicious identity is admitted.
Anonymity encourages this sort of thing, of course. Again, Pending Changes would have helped
The Wikimedia Foundation has so far not really cared very much about content quality. They do not measure it, and don't know how to, by their own admission. Their metrics of success are the number of articles, the number of editors, the number of edits (more is better!), the number of page views (Alexa!), and how many millions in donations they take. Little if any of this money goes towards measuring and improving quality. Most of it is spent on their software engineering and product development department, which represents two-thirds of the 200 or so Wikimedia staff
. They are approaching Wikipedia more like Facebook than an educational project. Quality assessment and real-time quality control, the job of sifting through all the millions of contributions, is left to all the volunteers, who are stretched
... and unlike the Wikimedia Foundation staff (many of whom are not really skilled professionals, but simply Wikipedians who have managed to join the gravy train), they are not getting paid. Short version: The Wikimedia Foundation now takes $50 million a year in donations (compared to just $2.5 million six or seven years ago), and they don't really know what to do with it. It's not making Wikipedia a more reliable reference source.