This is interesting.

Obviously, I don't have stats on things like the % active accounts vs inactive and such, so this is pure speculation.

If you look at the hot sorted posts on r/GothStyle they seem to get around 100 or so points per post. Note, this isn't a direct translation into upvotes. It also says there is 145 people online - Does that mean roughly 2/3 of active users vote stuff to hot? ~100 people holding up a niche community with a fraction of those the posters themselves.

So in effect ~0.1% of a subreddit's subscribers makes things happen. I always baselessly suspected that Reddit fluffs up the numbers to make engagement seem like it is much greater than it is, but this is 1000x smaller than the sub count suggests.

I'm sceptical of my maths here but r/PCMasterRace is similar. Out of nearly 8mil subscribers, roughly 8000 online.