Despite Microsoft's occasional and random plea of how they encourage open source, it is obvious they are vehemently opposed to it. They do, after all, make a name for themselves by being the opposition in just about every market they enter. Recently, they are taking their hatred for open source a bit farther. Now, they are demanding royalties from various open source software suites. They claim that many pieces of software violate their patents, including KDE and the cornerstone of most OSS, the Linux kernel. It goes on, with them also demanding royalties from OpenOffice and others, citing each of these violates dozens of different patents. With Microsoft's partnership with Novell, many have feared that Microsoft would make just the move they are now, claiming that the partnership automatically means they are correct in their assumptions. Some fear what this will bring:

Industry insiders are now weary of what may come of Microsoft's experts. If Microsoft convinces the patent system that it is right, the open-source industry could face potential meltdown. Eben Moglen, executive director of the Software Freedom Law Center says a massive war is about to be waged on the patent battlefield.
No matter how much Microsoft screams, however, it would be very hard to crush OSS. The existing infrastructure is gigantic, and, when factoring in embedded devices, you have billions of potentially "patent-infringing" products. Is Microsoft about to bite off more than they can chew? Personally, I hope so. The last thing today's software needs is more licensing.