A flurry of legal activity has erupted over a piece of software called WoWglider. The software (see here) will play your World of Warcraft character for you while you do other things. WoWglider's FAQ states bluntly that using the software is a violation of WoW's terms of use, and that your WoW account may be closed if you are caught using it. However, the FAQ also points out the various steps taken to make WoWglider difficult to detect.
When the creator of WoWglider, Michael Donnelly, received notice that Blizzard and Vivendi considered WoWglider to be a copyright infringement and a violation of the Digital Millennium Copyright Act, he decided to strike first and commenced a lawsuit seeking a declaration that WoWglider does not infringe any rights.
Blizzard and Vivendi have now filed a countersuit claiming various infringements, including violation of WoW's terms of use, copyright and trade-mark infringement, violation of the DMCA (by circumventing copyright protection), unfair competition, and tortious interference with contractual relations. The countersuit alleges that by creating and distributing WoWglider, Donnelly's company is encouraging and enabling WoW subscribers to breach their contracts with Blizzard.
Coverage at: http://tinyurl.com/25h3kp (Gamasutra)
and at: http://tinyurl.com/2m2hys (Game Politics)
WoWglider's Complaint here; Blizzard and Vivendi countersuit here.