Like does content get mirrored to my instance and then mine distributes it ala BitTorrent or is my instance it’s own thing?
Sure, but the server calculates the hot/active every 15 minutes regardless of whether or not you browse it. It’s calculated on a timed job so it’s always fresh and ready for everyone.
I was unaware that was the case, that’s pretty expensive and inefficient to do it for every user (because each user’s “Subscribed” feed is likely different) every 15 minutes regardless of how recently they’ve visited. The inflection point is probably lower for the benefits of even single-user instances in that case.