"There is no reason to believe that GNU/Linux has any greater risk of infringing patents than Windows, Unix-based or any other functionally similar operating system. Why? Because patents are infringed by specific structures that accomplish specific functionality," - Dan Ravicher, author of the study Microsoft cites
The study shows that when it comes to software, open-source varieties face fewer patent threats than proprietary ones, Ravicher said. "If one believes the proof is in the pudding, open-source software has much less to worry about from patents than proprietary software."
"Consider this—not a single open-source software program has ever been sued for patent infringement, much less been found to infringe. On the contrary, proprietary software, like Windows, is sued and found guilty of patent infringement quite frequently.