yeah but as far as advertising, they are usually one shot and once in a while. If I designed an ad bot I'd do a search for existing subs with relevant keywords and mass post artificial conversations or threads, as a numbers game. Which happens for example in r/showerorange. Big for a niche sub, but every few months I catch a post about showerheads on sale before a mod removes them. The smaller the sub, the less that numbers game has an effect, and drawfs in comparison to default subs. Manipulating karma has been long know how to do by veterans on here, so I can really only let my trust down a little with handfuls of smaller subs. It it all but a guaranteed equation that big sub = more bots and sublim ads (i.e. astroturfing). It's actually how reddit continues to survive, we can just keep making more subreddits. To make matters worse I see definite vote manipulation. Rule of thumb: if there is a brand in post, there is high likelihood that the most is.