lawsuits in it's wake Microsoft has clearly declared it's intolerance to competition, although they've been beaten in the patent game as well.
Linux and all open source products for that matter are reasonably resistant to patent onslaught due to the nature of open licensing. I can comfortably say that Linux has been the single biggest influence in driving Microsoft innovation. Microsoft may not be able to destroy Linux as a competitor but that will certainly not stop them from trying to thwart it's success. Microsoft can still sue companies for using patent infringing open source within their commercial products or services, the Microsoft/Tom Tom case is a good example of tactics used to deter corporate uptake of Linux.
Microsoft and Amazon have recently entered a patent agreement which includes the Kindle and it's Linux based operating system. The agreement is likely an effort to avoid a lawsuit. Aside from the tactic mentioned above, what's most concerning is that Amazon's Elastic Copute Cloud services (EC2) are a major competitor to Microsoft's Azure. Canonical's Ubuntu Enterprise Cloud infrastructure (UEC) is compatible with EC2 and is likely going to stir some interest in the Microsoft camp. Being a private cloud infrastructure, UEC has an edge but it could do without Microsoft patent mischief.