Good point, we probably need to emphasize this a bit more. We are trying to convince people that GroupieGuide offers groups a fully-functional customized website that they can call their own. On Facebook, Meetup, Google/Yahoo Groups, groups aren't able to express themselves with their own design and branding. GroupieGuide only has a single link back at the bottom of the group page.
May be you can use Facebook Connect to take down the sign up barriers, and this way, you will also get promoted in your new user's newsfeed when they join / create a group.
But the value prop of what features I would need that Facebook Group doesn't have isn't prominent enough.
But I would need to be convinced why I should use these groups instead of Facebook Groups, when my friends and I are already all on Facebook.