Here is how I believe they are operating. They cannot outright "accept" anyone right now because they sent out enough offers to fill the class after the january 15th deadline. Therefore they have to wait until the february 15th deadline so they can count how many spots are open. So, if you were interviewed between that time, or were "waitlisted" from an pre-dec interview, they won't "accept" you until that time.
As Dr. Lippman said during our interview (and probably yours also), after admissions reviews your app they will accept or reject you. At this point in time if you are accepted you are put into a list of other accepted students, waiting for a spot. So, it basically is a waitlist.
Dr. Lippman also told us that he expects 20-30 spots to be open come feb. 15th. I've also read in past years that a fair amount of spots open up after the second deposit is due ~ april 15th.
Hope this helps, and if anyone else has anything to add or change, feel free!
