Yeah, that got old very quickly, although things like the old Reddit switcharoo* always got an upvote, but the original comment needed creativity and the stock reply needed to link the the previous example. It was cool that it was a different experience each time and that the network grew, occasionally branching, and had maintainers that made sure you could follow without hitting a deleted part dead end.
* after half a year I had to use a search engine to get the name
But here I wrote all of this, instead of just the word “This”
I don’t think you can count the sites that just mirror Reddit comments.
Searching on lemmy.ml shows the top being several !news@hexbear.net megathreads with comments in the thousands, then that !asklemmy@lemmy.ml post you highlighted, more !news@hexbear.net threads, then a !meta@lemm.ee megathread about Hexbear’s federation. I guess we can see who comments the most.
I liked this !imageai@sh.itjust.works post Your username is the prompt, what did you get? which has 1618 comments.