People who say RightRightRightRightRightRightRightRightRightRightRightRightRightRightRight when you're trying to tell them something.
Or, yeahyeahyeahyeah really quickly. Really annoying.
Oh, you mean like Paul F Tompkins!
I'll run get the bullet
Stir that pot, DFK!
Another contribution that may or may not have been mentioned:
Calling the internet the internets, the interwebs, intarweb, "teh" internets, any mention of the internet running on "tubes," and the joke that Al Gore invented it. If you've done this, you're a dumb guy.