Best Practices for getting your group up and running?

I'm taking it slow in getting my Best Practices for Event Hosting group up and running - haven't invited anyone yet, while I see what the bugs are and figure out how to create a welcoming environment for when people do eventually get invited. (Thanks to those who have joined already anyway!) I'm curious about what you're all learning.

First: the hurdles to participation. Are new invites finding it easy to jump in, or is the fact that they need to enter the group through the link in their email making it harder for them to get involved? Are there other hurdles getting in the way?

Second: How to set the tone, expectations, etc? I love what Brandi did for The Marketing Crowd, laying out the guidelines for the group in an article and creating a sticky/locked post in discussions with a link to the article. There's not a way to "sticky" an article, but her clever strategy with the discussion post does the trick of making sure people will see it front and center, even months from now.

What other ideas are working / not working for stimulating activity in your groups? It's looking to me like it's easy to get people to join a group, but not as easy to get the participation ball rolling. Let's throw our ideas into this thread and figure it out as we go.