Microsoft can't swing a dead IP protocol these days without hitting a patent-infringement lawsuit. First there was i4i, the software company that successfully sued them for ripping off their HTML editing software. Now a previous lawsuit, alleging that Microsoft stole anti-duplication software made by Uniloc Inc., has been given new life.
The only good news for Microsoft is that reopening the case also reopens the question of damages. Uniloc was awarded a cool $388 million the last go-round, and in the appeals court ruling the court found that figure "fundamentally tainted." Thus Microsoft has a good chance of shaving off some damages (though also an outside chance of seeing even more).
There's also the fact that Microsoft's retired co-founder Paul Allen is currently suing the entire Internet. So if that works out for him, it can't be a bad thing.