User blog comment:D. Cello/Brotherhood's Multiplayer Beta Exclusive to PS3/@comment-3139944-20100616221228

It's probably on PS3 first because it was first developed for that console. @ E3 the only consoles running ACBH were PS3s.

I'm suggesting the XBOX version will be a port, and the PC version will be heavily delayed (Maybe we'll get free DLC's like last time:D), and have DRM installed.