Mobile social community MocoSpace has topped six-million registered users, just over three months after it reached the five-million-user milestone.

MocoSpace users can create profiles, upload and share pictures, chat, IM, blog and otherwise communicate from within the application. According to a recent report from Openwave on the North American mobile social network market, MocoSpace members spend an average 6.05 minutes per session - much longer than they spend with social network leaders MySpace and Facebook. The Openwave report found that MySpace mobile users average 3.79 minutes per session, while Facebook mobile users spend a mere 1.89 minutes.

The Boston-based MocoSpace credits word-of-mouth, with its current members inviting their friends to join, for much of its recent growth.