Last I checked, the original Silkroad strongly enshrined PGP encrypted communication between seller & buyer into the way these marketplaces are run. So theres

Last I checked, the original Silkroad strongly enshrined PGP encrypted communication between seller & buyer into the way these marketplaces are run. So theres no gain for them, as they can't get to whoever is selling/buying. They would just be facilitating the sales.