Probably not right away, that would be too big a hit to a stock that's already had a ~30% dive. Apparently they are too far down the open source path to turn back now, and are going to hit the afterburners instead. We could be seeing Linux ads at the Superbowl again, minus the lost-looking little boy. IBM is on the ropes and is going to come out swinging.
They can't do it with P.R. and advertising.
That might make Linux fanatics and advertisers happy, but I don't see how that will change the behavior of their customers. I kind of hope it wouldn't. Microsoft/Intel may have benefitted from big ad campaigns in the past, but that was only because what they were selling was the market (powerful consumer-level pc's and somewhat useful software) itself.