I don't know how this works on the desktop web site, but on the saidit app the top-of-sub banner only lists the subscriber number. This isn't super helpful in figuring out if a given sub is active, since new users are subscribed to all by default.
If that's not being done due to privacy concerns, then maybe a less user-focused statistic like "number of posts that have been read on this sub in the last 24 hours" with a rolling 24 hour window and a randomized update interval?
[–]raven9 2 insightful - 2 fun2 insightful - 1 fun3 insightful - 1 fun3 insightful - 2 fun - (0 children)