Has anyone made an effort yet to do the evident thing, and simply build a social service that lets you have separate groups of friends for all features?
The problem is that nobody wants to present their users with a gigantic list of contacts on first login and ask them to sort and organise them into groups. Instead, everybody just lumps all the contacts together so that the user is least inconvenienced at first, only to later experience problems. Google is in a pretty good position to tackle this, since a fair number of people who already have Google contacts probabl…
Distinguishing between for example work and personal contacts seems pretty hard, I'd say even for google.