Yup, Microsoft loves to spread the FUD (Fear, Uncertainty, and Doubt) around in copious quantities. The latest claim is about 235 I believe. It would be fun to see them try for some legal warfare. IBM, Oracle, and Novell (yes, I know they're in with MS, but Linux is their business and they'd probably join the fray against them) give Linux some serious legal teeth. (IBM has been around in one form or another since 1888, looong looong before Bill Gates even thought about buying DOS and licensing it to IBM to jump start Microsoft.
And in the end Linux would still be around. After all, they can just work around the patents and keep going while the crazy legal war is going down.