"Darknet-based drug marketplaces are frequently used by PWUD. 'Empire Market' , 'Hydra' (in Russia)  and other darknet markets operate similarly to regular online marketplaces: they give vendors and buyers a platform to conduct their online transactions on. However, darknet-based drug marketplaces are more difficult to access as they require special software which encrypts computer IP addresses (e.g., Tor Browser). Transactions are anonymized and performed with cryptocurrencies (e.g., Bitcoin); hence, darknet markets are also called ‘cryptomarkets’. In addition to making purchases on the cryptomarkets, users can also exchange information on the availability of particular drugs, experiences from using them, their effects and potential harms via integrated online forums [15–17].
"The use of drug marketplaces and drug-related online forums to facilitate harm reduction has started to gain the attention of researchers. A number of studies have shown that such online platforms could bring new opportunities to provision of harm reduction services [18–20]. Social media platforms have also shown potential to bring greater access to harm reduction services among PWUD [People Who Use Drugs] . Harm reduction interventions via online platforms are often referred to as ‘web outreach’, ‘online outreach’ or ‘netreach’ work [22, 23].
"Web outreach work implies that harm reduction workers contact PWUD through online platforms and provide them with harm reduction information and counseling upon individual requests of users or distribute harm reduction information publicly via online forums. Such work helps to encourage risk reduction behaviors among hard-to-reach populations of PWUD, who do not attend brick-and-mortar harm reduction facilities [22, 23]. Moreover, the COVID-19 pandemic has introduced social distancing measures and shortages of medicines and harm reduction supplies, which makes it more difficult to provide in-person harm reduction services [24, 25]. Web outreach helps organizations continue to provide harm reduction services during the pandemic."
Davitadze, A., Meylakhs, P., Lakhov, A. et al. Harm reduction via online platforms for people who use drugs in Russia: a qualitative analysis of web outreach work. Harm Reduct J 17, 98 (2020). doi.org/10.1186/s12954-020-00452-6.