What an interesting topic... for once.

Apple: More expensive, would be slower right before the new one comes out, extremely hip for no reason
Microsoft: Third party apps, fishy screen saver, that paperclip would be an NPC
4chan: All heads would be rage faces
Myspace: Would be out of business
Facebook: You would know each players real name, where they live, and what movies they like.
US Government: All players would be broke
Nintendo: Would be a family game
NYN: see 4chan