The second workshop on large scale recommender systems will be at SIGKDD in Las Vegas this year.  One of the main topics is the Netflix competition and Jim Bennett of Netflix is one of the co-chairs, so there should be some interesting stuff in that area.  Plus all the other cool stuff going on with recommender systems (yes, there is other work being done on them!).  Another of the co-chairs is Daniel Lemire, whose blog never disappoints.

The paper deadline for the workshop is May 30th.