Thread Privacy (with buddy lists)?

[PK8]

Heya, I was wondering if something like this was possible to pull off. I was thinking about wanting to do something like this for a forum.

It should work a lot like say... Facebook's status privacy options. The poster gets to decide who can see his/her thread: The public, users he/she has added to their buddy list, mutual buddies (I don't know if that's asking for a bit too much), or only themselves. Of course admins/mods would be exempt from thread privacy.

I can see this being applied to forums which act more like user blogs.