I've been conceptualizing an open and decentralized identity system that would be based on the person's enrolment within organizations. Each organization participating in the identity system would provision something like an OAuth token to its' users for the duration of their memberships. These organizations could be employers, volunteer groups, schools, etc. Third-parties could then leverage a user's collection of tokens as a "strength" of identity and build that into their platform.

I would use Twitter daily if I had an option to control an "identity strength threshold" where I would then only see comments from people who have implemented their organization memberships into an online identity.

Of course this is wildly conceptual and would be an impossible feat to implement, but it's a fun thought exercise.