Not a lot is known about the multiplayer aspect of the game.
Like the original game Saints Row, Volition are keeping the multiplayer aspect a secret until a lot closer to the games release on the  17th October.

All that is currently know about the games multiplayer is that it is going to be open world, some what like GTA IV. This information leaves a lot of people wondering "Will there be a Protect The Pimp game mode" this then leaves mixed opinions on if the game doesn't have the old game modes that it game wont be a proper 'Saints Row' Game with out some of the 'Classic Modes'.