Yeah, turns out it's not going to be happening after all.
While "Activision Blizzard" is going, only the Activison part will be showing up to smile for everyone. It appears the Blizzard part will be staying at home playing Wrath or tiddlywinks and sticking their tongue out at everyone, much like the girl in the picture (which I shamelessly have stolen from our sister site Joystiq who brings us this news).
But I can understand, because Blizzard really doesn't have anything to show at E3. I mean, it's not like they're making three of the hottest games on the planet or anything... Wrath? Diablo 3? StarCraft 2? Never heard of 'em.