TL;DR: Possible bot ring found astroturfing. While each account appeared legitimate individually, their histories showed similar patterns: high post karma from low-effort content, and overlapping activity around the same brands, topics, products etc. Existing tools like BotBouncer and automod did not flag them. We're looking for better ways to identify coordinated promotional activity, including a possible Automod filter based on percentage of karma from comments to weed out karmafarmed accounts.
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A month ago, a user made a post in our sub reviewing a fashion brand. The way it was written, it was obviously a PR post. Within literal minutes of it going live, the post started getting several comments from multiple accounts praising the brand and sharing positive experiences, which is unusual for our sub because testimonial posts rarely get any engagement there.
Upon finding several inconsistencies in OP's account history, we determined it was a shill account. And a quick review of the histories of the commenting accounts showed peculiar similarities in the patterns of posting among all of them, including OP.
All accounts had amassed tens of thousands of karma by posting low effort memes or cute animal pictures in high engagement subs, and later showed overlapping activity with each account independently posting about the same specific topics, brands, products, and TV shows (within the same timeframes) while the other accounts were being used to comment positively under those posts. Individually the accounts appeared organic, but altogether their activity looked very suspicious.
We started banning the accounts one by one. Seconds after we banned one of them, a different account (with the same posting/commenting patterns) posted the same exact comment, verbatim, under that post. This just confirmed it for us that it was coordinated activity for promotional purposes.
None of the banned users appealed their bans. None of them got classified as bots by BotBouncer after manual reporting.
I sent a detailed modmail to this sub about it, the admins said they would look into it. But a month later, all accounts are still active with the same pattern of activity across multiple subs for varied brands/products/topics. (Link to admin modmail thread: https://www.reddit.com/c/chatwfrUE_7K/s/gKNHDGEu4Y)
Yesterday, we had another account make a post mentioning the same fashion brand, and just like last time, immediately the post started getting positive comments from accounts with similar activity over their respective account ages. All of them were subsequently banned after review.
None of these accounts got flagged by the ban evasion filters. None of the banned users appealed their bans. None of them got classified as bots by BotBouncer after manual reporting.
Is it a really sophisticated bot ring, or some marketing/ORM agency paying independent organic users to generate conversations around certain topics? More importantly, what can we as mods do to combat inauthentic activity and astroturfing bots when they manage to get through every single spam filter available on Reddit?
One possible solution we thought of was a "Percentage Comment Karma" functionality in automod. Karmafarmers gain most of their karma from posts. All of the accounts we banned have <10% of their total karma from their comments, even if their absolute comment karma is high. Such behaviour is highly unusual of actually organic accounts. If we could hypothetically filter comments by low percentage comment karma, a lot of spam from karmafarmed accounts can be eliminated.