To add to the sibling comments, mastodon servers (or any other fediverse servers) are public and are searchable on the web (unless you really go out of your way

To add to the sibling comments, mastodon servers (or any other fediverse servers) are public and are searchable on the web (unless you really go out of your way to customize it to be private and not indexable). Meanwhile a private Reddit is similarly inaccessible as a private mastodon server. And Discord servers are just totally opaque and you can't search its contents on the web (even if it is public). You have to join the server and use Discord to do so. This is generally bad for information longevity. This is why people say Discord should be avoided for hosting discussions on Open-Source software.