Colleges manage their wait lists in a variety of ways, but are unlikely to adhere to a strict ranking of students.
If you are still interested in attending a college where you have been placed on the wait list, be sure the college knows it. Return the reply card (paper or electronic) by the deadline and then send a follow-up e-mail expressing your continued interest.
Once that is done, I recommend that you focus on the college or colleges where you have been admitted and that you choose the one where you feel you can be both happy and successful.
If the “top choice” college you are still wishing for does rank it’s list in advance (some do, some don’t) please don’t assume anything about the nature of that ranking.
The colleges that find themselves under-enrolled on May 1 might start going to their waitlists, which include students who are of good quality for that college but for some reason were not selected outright. Frequently, the students taken from the waitlist are those who meet institutional priorities. Those institutional priorities or goals are a strong factor in assessing who gets the calls.
So the answer I offer to your question might be that the entire list is not ranked (it is much larger than the college will ever use) and any ranking is not likely done according to pure academic strength. Whether you come off that waitlist or find unexpectedly great happiness where you’ve already been accepted, good luck to you!