Yea, the forums went online in Jan 2011, and while I think Dan did do some updates (I’m pretty sure it’s Dan in charge of the forum’s functionality), Vanilla stopped updating the version that (I’m pretty sure) we’re running on around a year ago, but as for just how outdated it actually is (in terms of functionality), it’s difficult to tell, particularly because of lot of the functionality appears to be limited to paid only users, and a lot of the user contributed stuff looks like it may be a bit buggy IMO, so I’d be doubtful of CoG’s willingness to use it. If the user contributed things do work well, a couple of them look like they could be nice to have on the forums, but I’m more than a little doubtful about whether the jump would be worth it, unless of course it can be done without any (potential) loss of information.
As for phpBB, the obvious question is: Are we big enough to warrant it over Vanilla, particularly over a jump two Vanilla 2 with the possibility of plugins for more features?