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.
@Benjamin its basically automatic e-mail in the sense that it doesn't matter what e-mail provider you're on but you can still contact each other across mail providers
Here you can substitute mail providers with social media platforms, and it happens ✨automagically✨, without anyone doing anything
To put this into perspective, I see hundreds of posts that aren't by people that signed up on wetdry.world on my home feed, and I can still interact with them, yet wetdry.world is my home.