The oldest entry in my blog drafts file is titled "No More Address Book". I wrote it in 2006, and it describes doing away with the need for address books and synchronisation by keeping one central service where we keep references to people. They change their addresses on their own, and we just use that central reference to find out how to contact our friends. I did note, however, that such a system would be ripe for the plucking by spambots and other advertisers. Fast forward 4 years and we all do this through Facebook, including the advertisers. Facebook is much more than that, of course, but it does exactly this too. Funny, isn't it?
Mokalus of Borg
PS - I'm not sure why I never posted that.
PPS - I might have wanted to write more about it, or polish it some more.