What is the Tildeverse?

What is a "tilde" server and what is this tildeverse thing I keep hearing about? In this video I'll give an introduction and overview to the ecosystem and talk a little bit about what you can find there and how to get started. Paul Ford's Medium post about creating https://tilde.club: https://medium.com/message/tilde-club-i-had-a-couple-drinks-and-woke-up-with-1-000-nerds-a8904f0a2ebf