‘Choice’ of social media platform or encrypted messaging app to buy and sell illegal drugs

•Different social media platforms were linked to different drug market contexts.•Use of multiple platforms for drug trading to buy from different seller types.•Drug trading context influenced weighting of platform security and convenience.•Social supply often took place through “taken for granted” social media channels.•Social supply could constrain seller ability to ‘choose’ a more secure platform. Social media is increasingly being utilized to facilitate the buying and selling of illegal drugs, particularly by young people. However, the range of social media and messaging platforms means people must make ‘choices’ around which platforms they will use to conduct drug transactions. Polymedia theory suggests that people use different media to manage their social relationships, ‘choosing’ appropriate channels or platforms based on platform features and the social context of the relationship. This paper uses polymedia theory to explore how buyers and sellers navigate platform ‘choice’ for drug trading, and how this bears similarities to the ways in which they move between different platforms in their daily lives. We conducted anonymous online interviews with thirty-three people who buy and/or sell drugs via social media and encrypted messaging apps in New Zealand to explore the factors shaping their selection of platforms for drug transactions. Our findings highlight the importance of the relationship between the buyer and seller in shaping how interviewees weighted the relative importance of platform security and convenience. Though more commercial drug sellers exercised considerable influence in directing buyers of drugs towards a given platform, this pattern was less characteristic of how platform ‘choice’ was navigated in contexts of drug supply between friends. In social supply contexts, platform ‘choices’ were often not explicitly made, but rather exchanges were channelled through platforms already in use within the social group. We highlight the tensions that arise between seller preferences for a more secure platform and buyer preferences for greater convenience in contexts of friendship. Our findings highlight the importance of understanding social media drug market engagement as shaped by broader patterns of social media engagement, and the distinctions between different social contexts and personal relationships, consistent with polymedia theory.