Just a bit of an update: Julie and I are adding more and more alternative social media sites to the S-MAP every week! Diaspora, of course, has been documented. Ello is on the way.
Those two are of course pretty well known. Lesser-known projects we’ve documented include Sone (the social network that runs on Freenet) and Evergreen (a social network proposed for Freenet).
We’re continually watching for more. I hear from people across ASM (on Twister, especially) about projects to add. If you have suggestions, please let us know.