You can already choose 6 characters: Mario, Luigi, Wario, Waluigi, Yoshi, and Toad. So far, I've had some success on my first day, having reached 9 players on at once :). There was already one Mario MMORPG called Super Mario Online that was announced on here by a user named "popibros1." Unfortunately, Super Mario Online did not stay true to the Mario series and was abandoned by the creator, although you can still play it. Other than programmed features, my game excels Super Mario Online in about every aspect. I'll put a direct download link on the first post in case you don't want to sign up to view those forums.