Dave Winer puts out a call for others building tools that support RSS and especially inbound RSS:

If you’re working on a social web app that supports inbound and outbound RSS, I’d like to help, so our products can interop beautifully. That’s the reason I’m doing this work, to establish a baseline for interop in the social web. RSS is the obvious candidate. If we didn’t have it, we’d have to invent it.

I’m actually not aware of any social platforms that support inbound RSS except Micro.blog. It would be great to have more.