The best thing I notice, the code is being supported buy cash. The source is here: https://github.com/tootsuite/mastodon and more details about the authour, here: https://www.patreon.com/user?u=619786

Dave Winer has been all over this idea for a long time: https://www.google.com/#q=scripting.com+federated+blogs and one idea that I don't see here (correct me if this is wrong) is the idea of static pages and ^light storage^ (e.g. S3) of text.