i'm... not gonna lie, i still don't get how this works. something about servers and diversification and communities
Basically, like email, there are server hosts and clients.
A server host being the place where all the accounts and data are stored, and clients being the system in which the user can access any server host, and allow a user to log into an account.
Usually the two come together, and usually in that case the client will only allow you to log into the same accounts as the host it was made for, but it will let you see posts from anyone.
Like how typically Yahoo email and Yahoo email access only allows you to get into a Yahoo email accounts, and recieve emails from anywhere.
These clients can be desktop applications or in browser systems. Basically you can get to it from either a website that supports it or from an app. Think Gmail vs mozilla firebird. In the desktop app variation, usually this will allow you to log into any account, not just one host's account.
And you can import and export your posts. Say you're getting off of mastodon and moving to another account. You can export your posts as a text document and upload them on the other account.