Just thought I with pitch in here, I was waitlisted after R1 and actually got in when the R2 updates came out. From what I heard if you dont get an update with R3 that means you are still waitlisted, otherwise you get an email saying your decision is available. I also spoke to one of the adcoms at an event in San Francisco recently and he mentioned that their waitlist is highly selective and relatively small, so that made me feel a lot better.
After I was waitlisted I sent a 1 page update with information on a promotion I got at work, a calculus class I had enrolled in and a leadership position I had taken on in a group I belong to.
I was waitlisted at 3 schools, so I realllly know this limbo feeling. But I wish everyone luck today and going forward! My fingers are crossed for you!