I was really excited about Novell a few years ago when they went on a acquisition binge. In what I remember to be a very short time period Novell bought Mono (an open source implementation of .NET) and SuSE Linux (the leading private label linux distribution in Europe).
In light of those acquisitions and the patent sharing on both sides of the deal, I think the deal is more about protecting the strength of patents in the face of the law than anything else. Both Microsoft and Novell have a vested interest in keeping patents strong in the courts. I also think both companies probably realize that some serious disruption to the strength of software patents is almost inevitable. Delaying that disruption as long as possible is good for the shareholders.