Sometimes it's obvious - the same user posting/commenting the same link across many related subs with very low signal and no other posting or commenting activit

Sometimes it's obvious - the same user posting/commenting the same link across many related subs with very low signal and no other posting or commenting activity. Or you see the same link and comment/post text posted by many different users. But this is just low-effort marketing. There's a lot of content that is relevant but also marketing. Burger/chicken restaurant twitter account screenshots getting posted to a default sub, for example.