While gmail never reached critical mass and completely closed off, it's anti spam efforts (among those of others) have made running a small mail server fairly i

While gmail never reached critical mass and completely closed off, it's anti spam efforts (among those of others) have made running a small mail server fairly impractical. Ending up like email would probably be the best case result for mastodon. It is interesting to think about what stuctural aspects of email prevented hotmail or gmail from reaching critical mass and being able to fully close off interoperability.