Next "big" idea...

Fully customizable social site, with a very fine control of who sees what. Every friend can be tagged with several labels. Every section/picture/blog entry can be shown to all, none or people who have certain tag. The problem is how to render it in some meaningful way, without leaving major gaps where hidden content is supposed to be. Solution (possible) - let viewers customize pages themselves, from the list of available modes, let owners set a general L&F.