Snapzu is invite only for several reasons. First, it allows trusted community leaders to be the "gatekeepers" of the platform as a whole, where no one can join without first being invited by a community/blog. Second, it creates a barrier of entry for people with any potential ill intentions, such as spammers and trolls, whom always seem to try and ruin the fun. Keep in mind that we do keep an invite request queue for people that discover Snapzu organically, and we do occasionally send out invites ourselves.