To counterpoint, haven't we been down that road before? XMPP, OpenSocial, etc. To be fair, it's market powers and network stickiness rather than abstract social

To counterpoint, haven't we been down that road before? XMPP, OpenSocial, etc. To be fair, it's market powers and network stickiness rather than abstract social or technical merit that have kept Facebook the incumbent. And for someone to dethrone FB, an interoperable social bus would probably be a good idea. Of course, that would not what would bring users to it (digital empowerment seems too much an abstract idea to explain to my mom, for example), but rather a killer app or a series of them -- like Instagram.