It's probably the FBI that infiltrated it. I have an image from 2010 in which a whistleblower points this out, as well as various things about the website that support the conclusion. Moot has cooperated with law enforcement from the beginning, of course, and it said that the FBI took over moderation on /b/ entirely (to moot's frustration). The hint for that was that whenever there were new janitor applications, they'd accept them for any board except for /b/. This was before the censorship and shills, but if it's true, you don't have to second-guess who's behind that.

I can't find the image right now, although I can share it later.