Just been on the phone with the Department of Computer Science. Apparently the admissions board is still in session, and (at least my) applications are still being looked at. Admissions (as in, Wendy) don't know exactly when the board will get back to them, but they're hoping it'll be within a week (so before then end of Feb). However, it could be longer than that because the board is really busy, there's lots of applications to process etc. Apparently international applicants get priority.
Try to keep calm people!
Edit: forgot to mention that I was also very explicitly told that the amount of time between hearing from them should not be taken as any indication towards getting called to interview or not. They really aren't sure when the board's going to get back to them, or when they'll have contacted everyone.
Edit 2: this is for the January 20th deadline only. YMMV for the March deadline.
Edit 3: after a follow-up email, it looks like they're hoping to tell us all either way by the end of next week.