Proposed federal government policy in Australia would force Internet Services Providers to block websites containing 'refused classification' content, including 'detailed instruction in drug use'. Websites containing material designed to assist people who use drugs to do so more safely could be blocked under this proposal. This paper reports selected findings from a web survey (n = 837) and online interviews (n = 27) with party drug users who engaged in online drug discussion, and observations of and engagement with online forums where drugs were discussed (n = 40). The project explored how the use of online forums to discuss drugs shaped patterns of drug use through: seeking and sharing of information, social norms or attitudes, negotiating 'drug user' identities, and accessing 'real-world' social scenes and drug supply. From the perspective of the young participants, public online drug discussion was a mixed blessing that both aided their efforts to reduce drug-related harm, but also had the potential to produce or increase drug-related risks. I discuss these findings in the context of the proposed internet filter. Blocking websites where people discuss drug use in detail will hamper efforts to monitor and engage drug users and to produce interventions that are responsive to new drug trends. It will also reduce access to archives of peer-driven drug information, anonymous social support, official rules and social norms that regulate discussion, and wide and varied voices not otherwise accessible through real-world networks. In 2012 the Australian government will consider the findings of the Australian Law Reform Commission's inquiry in media classification. Our submission to this inquiry has argued that blocking sites which contain ‘detailed instruction in drug use’ would ignore the complexity of balancing the potential negative and positive consequences of such websites, and may result in increased harm to people who use drugs.