To answer some questions for all, because I remember what it was like two years ago in your shoes not knowing **** about this great school and ****ty **** **** process:
The average of WL acceptances per year ranges from 20-25, which means around 20-25% of the class
has been off the WL. The disclaimer here is that no one has any idea what this current year will look like. It could be a slaughterhouse if Yale meets its yield nicely or a complete party if they need to fill a bunch of spots. YMMV to the max with this one
Timing of WL: Barbara may do things differently than Richard did, so again YMMV based on how or if she changes anything. WL calls used to go out on 5/1 as soon as they had the finalized list of accepted offers. Richard used to email first with a "we need to talk" and then you would have a phone call. You have around a week to decide and they would get you a financial aid decision before the deadline to respond. Deadlines can be extended within reason if you need more time to decide.
Yale's WL is ranked into buckets of 3. Those at the top of the list won't really find out they're on the top; they'll simply be the first to get the acceptance call. At the end of May, Richard used to email everyone to let them know which bucket they're in, how many spots are left, and how likely an acceptance is to come. I have no idea if Barbara is going to keep this going the same way. Do not ask whether they go down the list one by one or how else they actually pull from the WL; it's not scientific like that and the only people who know how the full process works are the ones in the admissions office. But the WL is ranked and that list was already made last month at the committee meetings. I suspect the list is fluid and sees changes over the next few weeks (e.g., if the top names are 10 girls and the class isn't balanced, they're not going to admit a class that's like 40/60 F/M); this is just my speculation based on some common sense.
Everyone can only hold 1 acceptance on 5/1. Remember that after 5/1, every school you are WLed at can see what acceptances you are holding but not what WLs you're on. Starting next month, schools that have accepted you will also be able to see what other acceptances you are holding but not what WLs you're on. Once a school rejects you, they cannot see any of this anymore.
As soon as you know that you aren't going to use your acceptance anywhere, please do the most courteous thing possible and inform schools as early as possible because it really is zero-sum at this point; someone holding an acceptance means another WL is not going to get in. Keep the anxiety as low as possible, focus on the acceptances you do have. WL movement is real but also highly unpredictable; you have no idea what's going to happen and it might remain that way until June. That sucks but you just gotta deal with it and there's nothing you can do.
Hope you enjoy Second Look for those of you who come. I'm not involved at all so I won't see any of you but it should be fun. Enjoy and good luck to all you.
Now, back to my hole of glory that is surgery clerkship..........................................................