If you haven't already, you should check out Virgil Griffiths Wikiscanner.
The WikiScanner database was made by extracting all anonymous edits from the publicly available Wikipedia database dump (which is released about once a month). According to Virgil:
In the WikiScanner database, there are 34,417,493 anonymous edits dating from February 7th, 2002 to August 4th, 2007.
There are 2,668,095 different organizations in the ip2location database which I am using to connect IP#'s to organization names.
Within the ip2location database, there are 187,529 different organizations with at least one anonymous wikipedia edit.
Examples of blatant misinformation being injected into Wikipedia are being tracked at Wired's 27bstroke6 blog:
- Exxon didn't hurt any critters
- Dell removes spyware accusations
- Wal-Mart's fighting the wage war
- Best Buy doesn't want you to know they suck
- Ronald McDonald orders deletion of McDonald's criticisms
- Starbucks removes link to comprehensive article critical of the company
There's also a nice list of edits at MaltaStar.
Apple is not immune to making their own controversial edits to Wikipedia. Computers in Apple's IP range edit Microsoft entries, adding more negative comments about their rival. Computers in Microsoft's IP range in turn edit Apple entries, adding negative comments about their rival.
If you've got a couple of hours to kill, check it out.