It's actually a fairly effective technique if you look at history. Apple always used to make commercials about their own products which led to Microsoft's "nit

It's actually a fairly effective technique if you look at history. Apple always used to make commercials about their own products which led to Microsoft's "nitpick ads". Now Microsoft's going positive and Apple has, for reasons I don't quite understand, chosen to go on the defensive (The most recent "Puddy" ad is obnoxious) I have no solid numbers to back it up but I personally like Ads where companies tell me why they're great much better than Ads that tell me why their competitor sucks.