If you’re a WordPress user then Gravatars will be nothing new to you. For the uninitiated a Gravatar (Globally Recognised Avatar) is an avatar that will follow you around the net as you comment on WordPress blogs (assuming the blogs have Gravatars enabled).
Simply go on over to Gravatar.com and register with your normal email address and upload your avatar and then every time you post here your avatar will appear.
Gravatar is also owned by the company behind WordPress – Automattic. :)