Kitty asks. Well, go to your instant, if not always reliable, internet knowledge source, Wikipedia. Here's the entry on Twitter:
You'll probably read it and think "So?" and "Why?" which are normal reactions.
But if you don't know who Jon Hamm is, then you're really not watching enough television. I jest. But I did provide a link. You can see he's hot. He's also on a cable show, so if you choose to do other things with your money, like eat, than spend it on cable, no one blame you for not knowing who Jon Hamm is. He has been called the next George Clooney. To which his response was, "But we already have a perfectly serviceable George Clooney." Cagey, huh?