This may have been discussed before. I'd like to see the ability to have a subset of my friends that I could for instance give access to certain blog entries. The idea being that if I want to blog about something highly personal, I'd like to have only the subset of friends see it, so I could share it with just them, not my 400 friends. Yes, I could cut back my friends list, but this is a social network. I think that would be counterproductive.