A German Talk about Fake Facebook Likes. So the are just Links how about them to solve Question for Bots?
https://www.youtube.com/watch?v=nmXACRrzLMA
So I am still aware of them. There are a lot of Forum who someone/ something register. Ask a Question for example:
"Maria Müller": Hey how to push my Homepage to get more Views?
5 Minutes Later:
"Hermann Steiner": Dont worry just Klick on ***********.com to push your Site to get the Number 1#!
... Well 2 Accounts with just one Post there Spam. So one of the Rule could be:
If Original Poster have an Post Count of <10 Post and when the Replay is <X(Min, Hour, Day) and the Poster have <10 Posts the hole Post (both) get Invisible and is marked as Potential Spam.
So a rule could look like this. I guess there is not that much CPU Power needed for such a simple task.