I had more than one friend, who I convinced to try mastodon. Trying to give them a good experience I'd check on them & respond to their posts.
They'd say: "I never saw your replies"
Turned out in each case they clicked a link & found they were "logged out" (on a different server) so sign up for that server, then another and another... on every server they had an empty account and felt alone.
We need quote-boost to stop this. An in-fedi link should stay on your home server.