We have published a 1-click install image on DigitalOcean. This reduces the initial time investment in self-hosting Mastodon substantially. You create a new droplet, choose the Mastodon image, and once it boots up, you are taken through an interactive setup prompt.
The only necessary information for the prompt is a domain name (it should already be pointing at the IP address of your droplet!) and credentials to some e-mail delivery service, like SparkPost, Mailgun, Sendgrid, or something similar.
Can you imagine Facebook closing registrations and saying “Sorry, we have too many users already, you can go sign up on Twitter instead”? And yet, this sort of situation comes up with Mastodon every so often, in regards to the mastodon.social server.
You see, Mastodon is decentralized. That means there is no “main” server. If mastodon.social actually disappeared from the face of the Earth, it would not bring down the Mastodon network at all.