I've been on the Mastodon for a few years now and while I knew other services existed on ActivityPub, I rarely used them and I didn't have an account on any of them until now because I thought the content would be the same because they're all federated. You can view a Lemmy post just as well on Mastodon. Now I'm finally trying out Lemmy and I'm discovering how different it is from Mastodon. Totally different content! I thought it was pretty cool to see.