In relatively early days of Reddit, before mainstream awareness, I thought it suspicious how clever or knowledgeable so many of the comments were. Better than any other general-purpose venue I could think of.
So, when telling people about Reddit, I'd sometimes remark that I suspected they'd enlisted a bunch of writer shills, to frontload and elevate their comments traffic.
Maybe it was all genuine and organic, and an artifact of the voting system and network effects, while the bar for quality was set so low by some other venues.
Though, years after Reddit was mainstream, I heard something about the founders originally writing a lot of the comments themselves.
I feel like even though Reddit has undergone various management changes, technology changes, site UI/UX changes -- the core demographic is still there and I hope they don't fuck that up. Once old.reddit.com is gone I'll know the shark has truly jumped. Or maybe someone intelligent will get reigns and understand that domain is not to be fucked with.
The same "initial implicit filter followed by gradual but inevitable reversion to the mean" dynamic explains your observations of early reddit without implying fraud, although it certainly doesn't imply the absence of fraud either. That said, "fraud" is probably a strong word for reddit astroturf in this present day and age where we have a (comparatively) planet-sized Dead Internet built on geological quantities of ads and slop.
They catch enough fraud that their customers get a positive ROI, but surely they don’t catch all of it.
It's one level further. The global intelligence apparatus is the real customer, and they economically reward those who would build the most-surveillable and/or most-opinion-influencing products and services.