Orkut profiles provide access control to pieces of information on your profile according to these 4 criteria.
1. Myself
2. Friends
3. Friends of Friends
4. Everyone
My suggest to Orkut would be that it should also provide access control based based on community membership, for e.g. I should be able to provide access to a certain piece of contact information to say my High School's community members even those who are not my friends. This might apply to other Social Networking sites too.
PS: I have nothing to do with Orkut/Google apart from being a user of their services.