This hack allows you to enable gravatars on your forums. Gravatars are the latest trend in blogging, but thanks to this hack, you can also use them on your phpBB.
Gravatars are "globally recognized avatars" and are used to have the same avatar show up on every site that has gravatars enabled.
To have a gravatar, you must sign up for free with the gravatar service. More information on gravatars can be found on the official website at http://www.gravatar.com