Microsoft has been rattling the IP cage over the past days. This is the best insight I've seen so far:
"Don't be blind to what Microsoft is really doing. They're not trying to stop the innovation or progress of OSS development. They are trying to stop the adoption of OSS by making these patent claims and then having the claims published in trade magazines and the web.
This is probably the most effective way to protect their bottom line. Going into court isn't what they want. They want doubt in prospective OSS adopters. With doubt comes the likelihood of sticking with what's safe. It's the same sort of campaign they "allegedly" helped SCO take-on to help stifle OSS adoption. From what I can tell, it had a impact for quite some time.
I am sure Microsoft knows that quite a few patents may not hold up. They'll only get bad publicity in the tech world, but to shareholders and the rest of the world, they'll look like they're protecting their assets. They had record profits last quarter and will continue to do so by spreading doubt in prospective adopters minds. It's so simple and yet so effective."