Steve Ballmer from Microsoft recently announced in Asia that Linux violates more than 228 patents.  Obviously, Ballmer was attempting to turn the crowd away from Linux and into buying Windows.

The interesting part is that the author (Dan Ravicher) of the study that Ballmer referred to has come back saying that Ballmer read wrong.  Dan Ravicher said that he believes that traditional commercial software has the same risks and may even violate more patents.  We have seen MS sued more then once over violation of patents.  Plus, let's not forget that MS has built its company on "borrowed" code.  Quick examples would be DOS, Windows, and most likely more.