@aral @cancel the difference is that with email part of the deal is that you can send a message to anyone else with email. Nobody would join a group of 100 like-minded individuals and have their own email network in addition to the Big Email one.

The fediverse is more like a loose collection of forum sites which intercommunicate - so while yes, there could end up an oligopoly as far as the masses are concerned, that doesn't stop the open fediverse from existing alongside it.