there are mainly two protocols out there, the fediverse and the federation (the protocol originated by diaspora). The federation now regroups 5 different projects. Have a look at https://the-federation.info
For more info about all those distributed social network, read @deadsuperhero articles on https://medium.com/@deadsuperhero
Why is this step necessary? mastodon.social might not be the server where you are registered, so we need to redirect you to your home server first.
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