I've been researching some specific technology needs, and figured I'd post here and see if anyone working in the collaboration/groupware/SharePoint world has any ideas. I've got my own research, and am speaking to a few others I know, but the community is bound to have some good input.

What I need is a Yahoo-Groups-like system, but it needs to be private and deployed on the LAN (for security purposes). Threaded discussions, with an email interface to contribute and receive updates. In a perfect world, it would build into SharePoint (we use it as an intranet platform), or at least lend itself to being displayed there. And while I am aware of future software possibilities, I can't wait for v.next in this case.

Indexed, searchable content, with opt-in and opt-out lists that can be moderated if needed, are also important.

Any ideas? Please - let me know!

Things I have considered: