Sometimes there will also be discussion posts "hey anyone know a good x for z?" written by a shill account where other shill accounts come in with product recommendations, supported by upvotes from other bots over any other evidence.
Kind of an interesting thread on the subject in the marketing subreddit: https://old.reddit.com/r/marketing/comments/vf5wmv/do_brands...
Basically people are saying yes, marketing on reddit is very effective, especially if you aren't obvious and using /u/mybrandname but /u/randomuser123.
This user is talking about starting a B2B company for this sort of subtle organic reddit posting, after having apparently a lot of success and thinking they can handle more clients than they currently do:
https://old.reddit.com/r/marketing/comments/1c05w7c/thoughts...
Have any subreddit mods been exposed as paid corporate shills?
Please don't misunderstand. The challenges and problems with content and moderation at both of those places are very real. But, relative to the most of rest of the internet, (a low bar to clear) they have coped very well.
Some of the headphone and electronics subs seem to have promotional accounts.
There are frequent issues in gaming subs with youtubers bribing mods to promote their content.