The most interesting way to go about it, I think, would be to prioritize breaking forms of interaction down to very basic forms. Most social media services are highly hybridized — post text, photos, videos, polls, checkins, etc., all in one place! Since this would be a modular server structure, the services don't have to be hybridized. Each could focus on being really singularly good at letting people do the one thing the service is most about.