Well, if my goal is to block all of Facebook's domains, I wouldn't complain if uBO happens also to block new.sub.domain.fbcdn.net even if it's not in the hosts

Well, if my goal is to block all of Facebook's domains, I wouldn't complain if uBO happens also to block new.sub.domain.fbcdn.net even if it's not in the hosts file :) Does uBO optimize these cases, though? E.g. if there's "apps.facebook.com", "connect.facebook.net" and plain "facebook.com", does it collapse to just 1 filter (facebook.com)? I see it says "880 used out of 881" which is the number of entries in the file.