There are rankings and levels in the server, but it's a separate thing from the "role" feature. The character roles don't really do anything; they're just, yeah, to represent the character that you associate with or like the most. I would've picked the Littlefoot role, but there's already three other people who have him, so instead I picked Cera.
For that matter, the rankings and levels don't really do anything either. It's basically just a tally of how much certain people have posted.