Recently I have been checking out Gravatar. I think it'd be great if it was implemented at phpBB.
Here is the link to a sample project, which will link to your Gravatar profile if the provided email address is associated with one. Sorry, a live demo won't work as Github Pages don't support PHP
[RFC|Denied] Gravatar Avatar
Re: [RFC] Gravatar Avatar
Ooh... Didn't see that 