I'd definitely prefer tags to a subforum. What tags should there be? Off the top of my head, threads tend to break down into:
Adventure
Non-adventure IC (such as the Tavern or the Screamer)
Proposal - for official proposals to vote on
Discussion - both stuff like the Peanut Gallery, and rules discussion that's not moved to a formal proposal yet
Administration - official announcements (granted we haven't really done any of that, but it might be good to reserve a tag for it)
On the other hand, the more tags there are the harder it is to filter correctly, so I don't think we should use all of these. The simplest split would be:
IC
OOC
On the gripping hand, it's useful to be able to find official proposal threads (as I know from trying to track things down when rewriting the charter) so I think my preferred list is:
IC - adventures, the Tavern and Screamer, etc
OOC - non-proposal discussion, including administration
Proposal - things that must be voted on