The extremists will be delighted; they get to propagate fear and use this as propaganda.
Moderate Muslims will probably consider it a bit childish (and may be offended, that's their right I suppose)
Anti-westernism will be bolstered a little more in the Muslim states
And people like myself just feel a bit embarrassed to be on the "same side" as these people.
Now, if someone wants to sit down and discuss how we could perform a grown up show of strength and unity against extremism then I'm all for it.
(I think the first point is the most important one; clearly this is going to backfire because it is the reaction the extremists where looking/hoping for. It's progressing to the point where they don't need to bother trying the actual terrorism any more - certain elements in Western society are scared to death and reacting to just words...)