Facebook has an AIM screenname. It's not being used for much yet, just sending out invites to join the service from folks who upload their buddy list, but we see potential. Whether or not Facebook will take advantage is something very different. You can already poke and get messages via your cell phone with Facebook Mobile, but very little appears on the site about the new IM interface. At the moment, sending an IM to "Facebook" gets you a boring "if you are not on Facebook, please sign up now" message. Come on Zuckerberg, get it together. This could be a great new way to poke your friends, and we doubt Facebook cares much about a few lost pageviews. Going to my browser to poke Jason McCabe Calacanis is just too much work.