Sounds interesting, does it involve a third party library to use?

Doesn't look like it Hoffie. Just use their registered email in the gravatar image source. I'd be willing to try it. I'll see if there is a way to set only specific avatar ratings on the Gravatar site and link that information here.

Actually, after looking it over it looks really simple! http://en.gravatar.com/site/implement/ Has all the details on how to implement the Gravatar service.

I see, so it works on the Gravator's own server? If so, the integration will be quite similar to what facebook/twitter integration looks like for web applications. Interesting, I will take a deeper look later tonight. XD

It does look neat. I found the code on css tricks and was intrigued... I figured I'd pass it on and see what others thought.

There's a downside to using gravatar though.
I use to be really popular, but I find not a lot of sites use it anymore..

The downside is you have to have some kind of moderation system. Because what if they have an inappropriate avatar? You still need to be able to turn it off, and delete it from appearing on your site.

I've seen it used, some places...

Plus I found that if you use this code:
You can set the rating by changing PG to G.

User item galleries? Or a trophies spot maybe? Like... "user has acquired -number- of -item class-" and it displays them? o~o

I've already seen it done on TaleofDragons.net. If you ask SilverKitsune she may share the code. ;3

Some people lie though when they upload their avatar.

You still need a moderation system.

For example, having a new permission. Like "Can user have avatar?"
If set to yes, they can have an avatar, if set to no, they've been banned from having an avatar due to misusing the feature.

True... Would be an easy thing to implement I think. Send the avatar through an admin approval process. If the avatar isn't acceptable force one of the identicons instead.