Don't think of it as yelp, think of it as Alibaba/AliExpress.
Sellers can always cheat, but it's harder and the risks of being booted off the site if you are a crappy vendor are higher as well.
It is rather naive to call that 'rather naive' given that the black-markets have functioned well since January 2011 (so, coming up on 4 years soon). I don't think it would take scammers 4 years to realize that reviews can be faked.
> when even yelp, which is supposed to be completely legal and reviews completely legal businesses has obviously manipulated reviews.
Yelp doesn't control purchases of services and take commissions and only let buyers review, so it's in a different position from the operators of a black-market.
> As I have mentioned before, the police can get you online the way they usually get you -- by having an undercover police agent pretend to be the seller.
So why don't they? Why are they ignoring the infallible wisdom of the great hristov?
Remember when you're buying anything but pot or shrooms through the friend network you don't know what you're getting or how stepped that coke is.
edit: Also, these sites directly observe transactions plus financial exchange. That gives them a lot more tools to detect straw vendors. What lengths are local cops willing to go to to catch people buying personal use amounts of drugs, particularly when anyone can claim their house was used as a drop address.
Virtually nobody has been prosecuted for purchasing drugs on silk road; the only limited attempts so far look to me to be attempts to build cases against the vendors [1]. The guy in that article has purchased narcotics from someone in Washington.
[1] http://heavy.com/news/2013/10/silk-road-drug-buyer-reddit-ar...
Because anyone can write reviews on Yelp, but getting privileges to write darknet reviews is fairly difficult. And IIRC if anyone who you invite into the review system tries to astroturf, then you and everyone else you've invited automatically get banned also.
Except this method doesn't work online because they can't prove you are the one who ordered it.
Anyone can order illicit material to any location and with any name over TOR. Without corroborating evidence, no court would convict purely on the involuntarily act of receiving mail.
So this is not some panacea for getting higher quality drugs. It is not even something that will ensure your safety from the police. As I have mentioned before, the police can get you online the way they usually get you -- by having an undercover police agent pretend to be the seller. In fact it would be much cheaper and more effective for the police to collect addresses from an illegal drugs site than the dangerous and tricky business of using undercover agents on the street.
I think the economist is being very disingenuous by cheerleading for these online sites. These are not safer from police or drug purity standpoint.