The new profiles allow you to poke around your characters' gear and stats, view your progression through the game's difficulty modes, and see just how much you love your Witch Doctor compared to the other classes. And when you tire of reminding yourself how awesome you are, you can paw through your friends' profiles too. Your flatmate could really use an amulet upgrade, and you should take any opportunity to tell him so.
Says Blizzard, "We like profiles so much that we plan to add even more functionality to them as Diablo III evolves, including detailed statistics and tabs for achievements and artisans."
Check out the new toys on Battle.net.