Whenever a resource has more than X items to return, the web service should return only X items and indicate how many items remain. Last night the old WS was effectively DOSed by one client who wanted to retrieve all of Mozart's releases. he query would time out and the client would re-try it. The load on the servers shot through the roof as a result.

UPDATE: should be implemented as described in the new spec:

http://wiki.musicbrainz.org/User:kuno/ws/2