It was already kinda figured out in the article. Examining the link 'neighborhood' is an effective way to determine spam within a network. The major players in search, social and email use this technique as one of their primary spam filters.
It's also important to understand that in any high stakes game sniffing out the bad actors is always going to be a never ending cat and mouse game, so no one solution will put an end to it.
but detecting spam is really just a way to filter out "legitimate" popularity from "illegitimate" popularity - it's still relying on popularity as a signal for quality.
It's also important to understand that in any high stakes game sniffing out the bad actors is always going to be a never ending cat and mouse game, so no one solution will put an end to it.