I am still learning this whole thing and I ended up creating accounts here and on Mastodon. Is that necessary or do I automatically have a Mastodon username with my Lemmy? I used the same stuff on both accounts, can I merge them or something?
Edit: thanks everyone, I can’t respond to each comment while I’m at work, but I appreciate every one of you!
Mastodon has an API of its own, just like Lemmy. You can follow/respond/like things cross platform, but the client apps need their own special API for sending data to the server.
It’s a real shame, because the ActivityPub standard that makes following other servers possible also has a spec detailing how to do client/server communication, but very few ActivityPub servers have bothered to implement it.
Do you know of any that are accepting new users?
The only serve software I know of that implement the client-server API is Fedbox. There’s a server running it on https://federated.id/ but it doesn’t have a frontend. You can only use it with client apps like AndStatus. Don’t expect anything as polished as Mastodon or Lemmy.
I have shortly looked into making some kind of bridge so you can use the same account for a self-run Lemmy+Mastodon server, but that’s quite a big pain to set up. Sadly, combining accounts just don’t seem practical.
That said, absolutely nothing is stopping you from following a Lemmy community from Mastodon. Just subscribe to @community@example.com (so replacing the ! with an @) and you’ll get every single post and comment on it in your feed. If you use something like Fedilab it’ll almost usable, I think?