But that’s only part of the story. Zhang, according to Bloomberg and other accounts, seems to also have been running a service through which unscrupulous businesses could pay to increase the number of “likes” on their Facebook pages, as well as their number of followers on Twitter and votes on other social networks. The site was promoted on the forum BlackHatWorld.

The business and its owner underscore what Facebook is up against as the social network tries to preserve the purity, and thus value, of interactions between users and advertisers. Zhang was no ordinary social media consultant; in an academic paper on computer security, he listed himself as working at the PLA Information Engineering University. That’s PLA, as in People’s Liberation Army. The university is the Chinese army’s electronic intelligence center. That’s quite an enemy for Facebook to be up against.