Also...someone OTHER THAN ME linked this? That's rare
Matrix is currently in a bit of a weird place as funding is low. Its alright, but dont expect Telegram-level UX. Element is also re-making their mobile apps as part of Element X.
I'm writing to you from mastodon (hence all my replies start by pinging you)
Lemmy does format some things in lemmy-specific ways, but other than that all our posts can be viewed anywhere, and I can slap any lemmy thread into my mastodon UI to reply to whoever I want
No I am not saying accounts are portable, but the content is. Your mastodon app has no idea how to handle Lemmy, and your Lemmy app has no idea how to handle Mastodon
BUT the servers that you're signing up to? They know how to share the content between eachother. That is because they all use the ActivityPub standard to exchange posts and account data.