Oddly enough this doesn't seem to be hurting the stock price. Usually news like this will tank a stock. I suppose it's because the current price isn't over extended.
I think it is because nobody believes it will actually force MSFT to stop shipping word. And with a market cap of 200+ billion, a payout to i4i wouldn't hurt MSFT too much.
This is just the lower district court order. Microsoft will almost inevitably appeal the case. In patent cases, the appeals court often takes an active role in scrutinizing the patent and the case, and it often disagrees with the lower courts.
So I would hold off on worrying about the verdict too much at this point. What happens on appeal is most likely more important.