The jerboa app does this, and it helps when searching for a community to see how many people use it, especially when there are multiple across different instances.
That said, I don’t really know how accurate their number is so maybe it’s not super viable
These numbers are super confusing right now.
- For a community on the same instance as your account (aka a “local” community) you’ll see the global subscriber count, including all subscribers from all instances.
- For a community who’s native home is on a different instance than your user account (a “remote” community), you’ll see only the subscribers from your instance excluding all subscribers with accounts on other instances. I assume this happens because subscriber counts aren’t federated so the only server that knows the full sub count is the canonical home of the community.
I’ve spoken to tons of people who attempted to subscribe to the biggest community on a topic but got it backwards because they didn’t see the full subscriber count on remote communities and misjudged their size.
This is a useful feature, but worth noting how confusing the numbers are. Liftoff should either explain them better than Jerboa, or consider fetching user-counts from the community’s server (though this violates the spirit of federation a bit, I don’t think there’s another way to get apples to apples numbers).