@mike @waltmossberg @Gargron totally right - his bad experience does seem a bit unfortunate, as communication on Mastodon between servers is pretty seamless. Yes you can click to others' home server pages where you're not logged in, but actually quite hard to do unless there was a link to it.
Your point well made though. The easiest thing to say to a new thing = no thanks, too hard, and then leave. Hope doesn't happen here.