Somebody using a National Rifle Association computer altered the Wikipedia article on the Sept. 11 terror attacks to strengthen the suggestion that Saddam Hussein's Iraq many have been involved in the planning and execution of the attacks.
Church of Scientology computers have been used to excise criticism of the church from Wikipedia.
A CBS computer was used to falsely claim that CNN correspondent Wolf Blitzer's real name is Irving Federman. This "fact" was added to Blitzer's Wikipedia biography.
And folks from The New York Times, Fox News, the FBI, the CIA and many other groups and organizations have also been busy cutting and pasting their version of Wikipedia history.
As the Web encyclopedia that anyone can edit, Wikipedia encourages participants to adopt online user names, but it also lets contributors be identified simply by their computers' numeric Internet addresses.
Often that does not provide much of a cloak, such as when PCs in congressional offices were discovered to have been involved in Wikipedia entries trashing political rivals.
In a recent incident, the press secretary for Rep. David Davis, R-Tenn., said he deleted unflattering information about his boss and his brother, a state representative, from their biographies on the Internet encyclopedia.
Timothy Hill used a congressional office computer to edit their
Wikipedia entries. "My job is to make sure statements about my boss are truthful and, sometimes, as positive as possible," he said.
Episodes like this inspired Virgil Griffith, a computer scientist about to enter grad school at CalTech, to automate the process with WikiScanner, a new online tool.
The free scanner grabs the Internet Protocol addresses used in anonymous Wikipedia edits in the past five years. By combining that with public information about which IP addresses belong to whom, the Scanner reveals Wikipedia changes made from computers assigned to many organizations.
Many of the edits are predictably self-interested: PCs in Scientology officialdom were used to remove criticism in the church's Wikipedia entry. But others hint at procrastinating office workers, such as the tweaks to Wikipedia articles on TV shows being made from CIA computers.
Many examples are being tallied at a page run by Wired News, which reported earlier on WikiScanner.
Griffith wrote on his site that he hopes "to create minor public relations disasters for companies and organizations I dislike."
Whatever comes of it, WikiScanner has a fan in Wikipedia founder Jimmy Wales. "It is fabulous and I strongly support it," Wales said.
© 2007 CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.