The DarkMarket is bringing the dark side to the digital playground that we call the Internet. Once upon a time there was a place on the net called the Silk Road but the FBI cracked down on it pretty viciously, Napster style. The DarkMarket is learning from its predecessor by making an FBI-proof system.
The Internet isn't all cat memes and listicles, there's a whole different side to it that isn't only frightening, but often illegal. This particular marketplace is even more dangerous because it can't be tracked by federal agents. This is because there isn't a centralized presence to be tracked.
If the FBI wants to stop the BlackMarket, it would have to track every single person that is purchasing anything off the site, a feat that may be too big for even the government.