Libravatar (from "libre" and "avatar") is a piece of free software to do federated avatar hosting. What does that do and why should you care?

Say you've got a profile image you like to use when you have an account somewhere. You want this photo to show up whenever you interact socially with a website. In other words, you want your blog comments, status updates, git commits or anything else you do publicly to be associated with that image.

Uploading your image everywhere is clearly a waste of time. What if there was a place where you could put it and where every website out there could access it easily? That's the idea behind Gravatar, the service that pioneered this approach and inspired Libravatar.