See Who's Editing Wikipedia
Thanks to Virgil Griffith and his Wikipedia Scanner that helps tracking the source of edits in the online encyclopedia, we know that some organizations like to edit Wikipedia according to their own agenda. Wired highlights changes made by Diebold on its own page, that some have liken to vandalism.
In no times, I was able to track down changes made by Nedap, another vendor of electronic voting machines, to the page on Electronic Voting. The change, which boils down to bragging about the fact that Nedap sold some machines in Italy, and dissing competitors technologies, has been done in six steps on the same day (Feb. 6, 2007, with a lot of rewriting performed on Wikipedia, not well prepared it seems).