I can understand, but i looks like that there all using the same kind of system...
As far as I know Bitcoin started evolving after the huge success of Silk Road (
https://en.wikipedia.org/wiki/Silk_Road_(marketplace)).
Be extremely careful if you set a black market. The first clients can be secret service agents. They can come with hundreds of
BTC and become your friends. Few month later you can be in a prison

.
I agree with you. The government agents are lurking in the dark marketplace used extra caution if you are going to engage in that market.