When the Silk Road website was busted in October 2013, the closure took out 13,648 different drug deals, according to research by US online safety group, Digital Citizens Alliance (pdf). Yet today, the dark web is teeming with dozens of new markets and thousands of new dealers serving a growing consumer base.

This week, a search of the revived Silk Road site, which has been back online since November 2013, showed 13,472 different drug deals. And according to a recent Reddit.com post, new darknet markets carry a total of 33,985 different drug deals – an almost threefold increase in darknet drug-dealing activity in just eight months.

As well as Silk Road, police forces worldwide must now add new sites, Agora, Evolution, Pandora, Blue Sky, Hydra, Cloud Nine, Andromeda, Outlaw, Pirate, BlackBank, Tor Bazaar, Cannabis Garden and Alpaca.

“Purchasing new and ‘old’ drugs via ‘darknets’ – underground, online networks permitting anonymous communication — represents a new challenge for law enforcement,” said the European Monitoring Centre for Drugs and Drug Addiction in a statement on Wednesday.

Though some are scam or fraudulent listings, the wider growth pattern is clear. And as well as these centralised markets, with many vendors selling to large numbers of customers, there are now dozens of boutique single-vendor sites, specialty shops selling only high-quality cannabis, or LSD, or cocaine to invited guests only. There is now even a darknet search engine, Grams, as well as a central repository carrying reviews for all darknet drug dealers, called the Hub.

Buying drugs online is no longer a niche activity

Buying drugs online using bitcoins was, just a few years ago, a niche activity known about and practiced only an avant garde technical elite. Today it is becoming much more commonplace, says Adam Winstock of the Global Drugs Survey. Of the 80,000 respondents he surveyed in 2014, 22% had sourced drugs online and 44% of those had done so for the first time during 2013.

“The growth of purchasing psychoactive drugs online in recent years reflects the growth of ecommerce more generally,” said Winstock, whose survey is the world’s largest inquiry into drug-user habits. “Convenience, product choice, price and user ratings make buying drugs online attractive to some users.”

Users like Jonathan, a 24-year-old web developer from London, agree, and say choice, safety and convenience make online drug sourcing easier than buying drugs offline. A longtime Silk Road user, he migrated soon after the site closed in late 2013. “After Silk Road was closed I went to other sites, first of all Blackmarket Reloaded. When that shut down, I hung around online and soon found Agora.”

'It felt safer than buying from some bloke in a club'

Agora is a darknet site hosted on the Tor anonymising network and is named after the anti-state, anti-taxation philosophy of Agorism propounded by the original Silk Road operators. Last week, Jonathan bought MDMA at around £30 a gramme there.

“The quality was spot on – and it felt a lot safer than meeting some dodgy bloke in a club,” he says.

As well as drugs, a host of other illegal products and services are for sale, including forged documents, secret foreign bank accounts, money laundering services, hacking techniques, phishing and spam tools, anonymous mail drops and weapons.

The US-based web crime group the Digital Citizens Alliance this month published a detailed report called Busted, But Not Broken: The State Of Silk Road and the Darknet Marketplaces, (pdf) which reported that “there is significantly more competition today than when the original Silk Road was seized”.

Dr Nicolas Christin of Carnegie Mellon University, whose pioneering 2012 study of the Silk Road (pdf) was the first to quantify that illegal marketplace’s economy, agrees: “Other markets have popped up, and at least in terms of items’ availability, it seems that they have mostly picked up where Silk Road left off.”

The Silk Road bust has hit darknet user and vendor confidence, however. “There isn't a feeling of invincibility that was pervasive last year at the same time,” said Cristin. “People have realised that, while the technological infrastructure provides good anonymity when used properly, operational mistakes can be very costly.

"Perhaps more importantly, the number of scams [such as market operators absconding with the cash register] has shown that these anonymous online marketplaces are not without risk either.”

Still reliant on postal services

Customers, and the sites themselves, are still reliant on physical delivery services. In the UK, the Royal Mail delivers 42m pieces of domestic and 2m international in the UK each day, including many containing illegal drugs from darknet markets. "Where Royal Mail has any suspicion that illegal items are being sent through our system, we work closely with the police and other authorities to assist their investigations and to prevent such activities from happening," it told the Guardian in a statement.

The new markets have suffered attacks, hacks and many have simply been scam operations. Silk Road itself was hacked and millions of dollars in bitcoin were taken this year. But the site’s owners have repaid 50% of the thousands of victims affected by waiving wages and donating commissions.

Gwern Branwen, who has documented the Silk Road from its earliest inception, told the Guardian the markets are growing far beyond the original constituency of tech-savvy drug users.

“Judging by the decreasing technical competence of users on the relevant forum, the black-markets seem to be reaching a wider audience and not just geeks. The black-market scene is overall growing, although it has fragmented a great deal. It does seem safe to say that it's recovered from the fall of Silk Road 1.”

The current fastest-growing market seems to be Evolution, which uses the inbuilt multiple-person escrow facilities of bitcoin, known as “multi-sig transactions”, whereby funds are only released from a buyer to a seller once a third party has signed off the deal.

Government: 'Anonymous tools are not totally untraceable'

The Home Office, which is responsible for policing the web and these illegal marketplaces, told the Guardian the issue was firmly on its radar. “We work with a range of UK and international partners to collaboratively address crime threats, including hidden-web criminal marketplace sites, and the use of fast-parcel and postal services to smuggle illegal commodities.

"Tools which aim to anonymise the identities of online users present challenges to investigations, but those challenges are not insurmountable, and numerous criminals who have thought themselves untraceable have found that not to be the case,” said a spokesman.

However, the technological future of the sector looks assured – and increasingly complex. New bitcoin software Dark Wallet is specifically written to facilitate anonymous bitcoin payments, and inventors Amir Taaki and Cody Wilson have stated explicitly that they believe the freedom to buy illegal drugs is a positive consequence of encryption, bitcoin and Tor.

“I want a private means for black-market transactions, whether they’re for non-prescribed medical inhalers, MDMA for drug enthusiasts, or weapons,” Wilson told Wired magazine this month.

• Privacy under attack: the NSA files revealed new threats to democracy

Mike Power’s Drugs 2.0: The web revolution that’s changing how the world gets high is published on 5 June on Portobello in paperback