I was just poking at my wiki, and wrote a thing that I'd never actually thought of before, but which addresses a concern held by some fans on DW a while back, who thought hubzilla would be just another silo and one where you had to know the right people to get in.
Except that that's totally not a thing that could happen, because:
You can do fandom on Hubzilla on any hub, even if it's not explicitly a 'fandom' hub.
And, of course, if you're on (for example) start.hubzilla.org, and connect with some fandom people, pretty soon you'll figure out who is open for registrations or has invites or whatever.
I started out on hub.disroot.org and connected with everyone on fandom.stopthatimp.net just fine, in fact, that's how I knew it existed...
ETA: if you start on one hub, then move to another, you don't have to start over, you just clone! Connections, webpages, cloud storage, wikis, and a number of posts can all move along with you and it's ridiculously easy to do...