As someone who's been through the whole waitlist ordeal with Duke, perhaps I can help answer some of your questions. I was on the waitlist for most of the summer and ended up being accepted only a couple weeks before classes started! I'm currently a 2nd year student.
First, the "alternate list" is the same thing as the "waitlist." Duke seems to prefer the former term for some reason. Unfortunately, Duke has historically had a policy of not telling students where they rank on the list. In fact, they refuse to even tell you if you're in the top or bottom half! Another interesting thing about Duke's alternate list is that it's supposedly "firmly ranked," meaning that showing interest, sending letters, etc. apparently will not change your standing on the list. I still did some of that anyway though, figuring it couldn't hurt to show interest.
I don't think anyone knows for sure how long Duke's waitlist is, but if I remember correctly I heard at one point that it's at least 100 or so applicants long. Unfortunately the number of students accepted from the list varies quite a bit from year to year, and will depend in part on how many applicants were accepted up front. In my class of 100 I think there are around 10 or so of us who were accepted from the waitlist. But remember, that likely means offers were made to more than just 10 people on the list, because some refuse due to already having other plans.
I posted a lot about the finer details of this stuff during that summer of 2002, so if you do a search for posts by me you'll probably find some more information. I've forgotten most of the numbers now. Anyway, I hope this stuff is helpful!
-Tom
