I just took a peek at the database and it looks like a good number of waitlisted students haven't hit the "accept" or "decline" buttons under their letters.
I imagine students who fall into that category aren't even reading this blog anymore, but maybe you can pass the word at school (this is mainly for Virginians, I guess): please be sure to accept or decline the waitlist spot.
Also remember that you can pull yourself off the waitlist at any time by hitting the "decline" button. So, if you accepted a spot a few weeks ago and your heart now belongs to another university, you can remove yourself from the list.