Gower's words:
About 15-20% of interviewed candidates are usually accepted. To fill the class of 120 the class is sometimes oversubscribed (=over booked) by up to 100. This occurs from January through March.
The wait-list is not ranked. When there is an opening, the entire list is reviewed. The composition of the class is looked at closely when selecting students from the wait-list. [I believe this is not uncommon, even when not explicit, where wait-lists are not rigidly ranked]. Greatest movement: April 15-June 15. After June 15, fewer than 10 applicants are usually accepted.
Faxes, e-mail, and letters that describe a continued interest in the medical school are most helpful to wait-listed candidates. [I am a believer in keeping such letters short and simple, not laying it on too thick, especially if WU may not be your first choice if you have other options].
Good luck all.