I'm not clicking a link to that site to get any additional context, but "Bots talking to bots" for the sake of stealth/viral advertising has been happening on Reddit for at least a decade (and almost certainly longer). Sorry this will be a novel of a comment.

My awakening happened when I noticed a specific trend of posts and comments in subs related to things like nutritional supplements, personal grooming, and things of that nature and it would be most easily detected in small subs with low user activity.

I'd see a post like "I need to find a new body wash, has anybody tried BoShiWah?" It would usually be the most highly upvoted thread in the sub with far more comments and replies than anything else in the sub. Comments were all posted within minutes of each other and shortly after the post was submitted, which would be highly unusual for a sub that only gets a few posts a week. These submissions would all be highly upvoted. The "conversations" would all be positive regarding the product and/or ask questions about it that would sound suspiciously like the script from a tv or radio commercial. And there would always be at least one comment like "where are you planning to buy it from" with a reply that contained a link to a vendor or someone saying something like "XYZ company has it on sale right now, here's the link".

I got curious and started looking at the specific user accounts involved in these posts and the comments/replies. It was a never ending supply of different accounts, some new, some old. The part that surprised me is that these accounts were also active and doing the exact same thing in larger and more active subs that were otherwise actively moderated. The activity that made them so obvious in the tiny subs was almost invisible in a post with hundreds of comments.

Reporting them rarely ever resulted in any kind of removal. The smaller subs aren't actively moderated. The admins don't (or didn't) really ever respond to direct reports. I would sometimes comment on my observations in hopes that it would persuade less savvy folks from falling for it. Sometimes, though, I'd end up with dozens of down votes for doing that (again, very odd thing to happen in a small and inactive sub).

At one point I got "noticed" and I was invited to a private sub run by users who report and track that specific kind of spam. Also very eye opening to see how pervasive it was.