A few days ago, Jon Udell wrote about the transparent society. I remember having a conversation with him a long time ago about this idea -- the idea that none of us has any secrets. We all can know each others' financial situation, relationship situation, what we do in our spare time, and so on. It was a fascinating idea -- the way this would force a change in our social contract(s). Imagine what life would be like if everyone could know how much money you make (and you could know how much money anyone makes). Or where different people are investing. Or spending their time. Or what TV shows they watch. Or who they spend their time with. If you could look at anyone and quickly learn everything about them, they'd have no secrets. Nor would you. It's both terrifying and liberating to realize that the number of subjects we consider taboo today just because they're against part of our social contract (as opposed to things we consider taboo because they actually hurt someone else) is rather large.
Brin has a book dedicated to it.