You are not logged in. However you can subscribe from another Fediverse account, for example Lemmy or Mastodon. To do this, paste the following into the search field of your instance: !email@example.com
Subscribe to see more stories about technology on your homepage
I am by no means an expert, but for the few people I use them with, they sometimes serve different purpose. I use more XMPP for everyday 1 to 1 messenging, and Matrix for group conversation of richer interactions.