E-mail said "about two weeks." They're going to start notifying R2 applicants of interview status on 1/27, so I wouldn't be surprised if we don't hear anything until just before that date.
That said, it's just as likely that someone not paying attention to ClearAdmit or GMATClub got off the waitlist already and we don't know about it since the universe of waitlisters is so small. In the mean time, all we can do is keep our expectations realistic so we're not crushed again in the likely scenario that we don't make it off the waitlist! Good luck to everyone! (But don't take my spot!)