Bob reminded of something that I have been wishing for. It would be nice if we could browse the member's profiles. I usually check the profile of a new member, and I sometimes find things in common from doing that. I gives me something to talk about, and I can send a PM with a little more personal touch than just "Welcome".
I think a mass mailing would be a good way to boot involvement.
Another thought is that we good have a posting of who is having a birthday during the week. That would give us the opportunity to increase interaction between us and maybe increase participation.
"Knowledge itself is power" Francis Bacon