So it's Diaspora meets a CMS? I thinking the issue here will be the chicken and egg problem - how do you bootstrap something like this without a killer app to drive adoption? After a certain critical mass adopts a system like that, all web applications start getting pressured toward supporting it too, but how do you ever build that critical mass to begin with? The whole point of the system is to prevent vendor lock-in, so what's the vendor's incentive to help make it popular?
I'm thinking the incumbents of each field that has a vendor lock-in problem could gather around this common platform and provide an open ecosystem as an alternative to all the monopolies that don't respect their users.