I keep trying to use that site, but I can't login (spinny wheel forever) to subscribe my account to anything.

Do I misunderstand fediverse accounts? I signed up to a Lemmy instance, shouldn't that login work here too?

Thanks, I should've been more specific, I've been searching but either find old dormant subs with zero audience, or (more often) nothing at all.

Would be great if there was a way to register interest in a subs that don't yet exist, it might encourage people to get them started.

Would be a shame to lose this week's momentum - though I'm having fun so far 🙂