People IRL tend to use cellphones. So many vulnerabilities in this. Let's say you are Bob the average lower to mid level IRL dealer. You probably sell out of your house. You probably have a lot of people coming and going to your house. They all probably carry cellphones. This pattern of heavy traffic can be passively identified. What is worse is that half of your customers are probably known drug users and this can also be identified. They might not be able to find your home with cellphone positioning technology, depending on how accurate it has gotten, but they can certainly narrow in on some restricted geographic area that has a large portion of known drug users going to it in patterns that are consistent with obtaining narcotics. Further narrowing would potentially need to be manned. This sort of attack is realistic and it probably doesn't require a warrant. Also I can't believe how many people who sell drugs just use their regular contract cellphone to do so. I sure wouldn't want to end up as identified as someone who a substantial number of known drug users frequently call for time periods that are associated with drug deals being made. Police can legally get the entire topology of cellphone based social networks without a warrant, it isn't a wiretap if they look at who calls who and for how long, as long as they don't look at communications. It is a trap and trace / pen register and requires absolutely no warrant, and all of this information is certainly stored by phone companies and ripe for LE picking and dragnet analysis. Give me Tor and mail any day of the week. Not to mention that from a vendors perspective none of my customers will know who the fuck I am so they can't possibly snitch on me with any info that the police can't readily get themselves, which is nothing. From a vendors perspective online drug dealing is infinitely more secure than IRL dealing.