There's some kind of SEO exploit that Google is unable to counter. Apparently, by creating bot accounts on a semi-reputable social media platform like LiveJournal, Baidu or Reddit and having them post endless links to each other from website X, website X is inflated on Google even if no humans interact with any of the bot posts/accounts.
I don't work in SEO and have never bothered to investigate this, it's purely a topic that keeps coming up in the twitter posts of one of the owners of Livejournal-spinoff Dreamwidth (their account is @Rahaeli).