I know some places don't actually send out rejections at all. Different philosophies, I guess. Some places you will just not hear from. I don't know if they hold on to applications in case they need to interview more, or they just don't want to deal with also sending out rejection letters. I guess if it gets late in the year (not now!) one could always call and ask...
Yaah, do you know which places? It would be nice to know when to actually give up on some of these programs. It's also making interview scheduling difficult.