Social media and on-line interaction can be as significant as the offline environment in shaping youth health behaviour, possibly explaining the association between social media and alcohol use by youth. Social media also presents opportunities for new prevention and intervention strategies. Social media are inherently social, and people are inevitably influenced by the interactions therein [5]. Ng Fat et al. propose that the association between heavier social media use and higher likelihood of more frequent drinking by youth could be due to cultural norms of drinking which are transferred through the on-line context [1, 6]. Prior research work on norms concerning addictive behaviours [7-9] provide support to this notion, suggesting that observed norms are a powerful transferer of health behaviours. The challenge of social media is that they are likely to distort the user's perception of reality due to user activity, contacts and various algorithms [10]. Perceptions of alcohol norms or the impression of how much others are drinking are often over-estimated [2, 11]. This poses a risk to young people who are particularly susceptible to social norms and can lead to many unwanted and harmful behaviour patterns, such as increased drinking. Ng Fat et al. did not investigate the effect of social norms as such, although they discussed youths' sociability both on- and off-line as a potential factor influencing greater alcohol use. However, their results highlight where the gaps exist in understanding how social media and on-line relationships could impact the behaviour of developing youths. Emerging research in the field suggests that social media and virtual interaction in general can be as powerful as the off-line environment in terms of shaping youth behaviour [12]. Ng Fat et al. defined social media use as belonging to social media sites, including Facebook, Myspace and Bebo. However, social media are much more diverse and manifold, warranting wider and more nuanced consideration. Research indicates that social media platforms differ greatly when it comes to interface and content [13]. Social media such as Facebook and Instagram are more user-orientated and on these types of platforms, users typically have a visible identity. Interaction in these services is based on people's mutual relationships and content is mainly shared among a certain set of other users (i.e. friends, followers) [13]. It is possible that, on platforms such as these, social interaction is more meaningful and social influence and behavioural diffusion occur more easily. Social media such as YouTube and Twitter are more content-orientated where networks are established around users’ shared interests. Other users or audiences are more far-reaching and often anonymous [14]. Young individuals are likely to turn towards more interactional social media platforms where communication is mutual [15, 16]. This could also partly explain the clearer pattern between social media use and higher likelihood of more frequent drinking among the 10–15 age group. It is noteworthy that Ng Fat et al. conclude that no direct evidence was found indicating that the rise of social media platforms could be contributing to the increase in non-drinking among youth [17]. While social media use has been associated with adverse health behaviours, the opportunities to employ different on-line platforms for prevention and intervention strategies are abundant. However, future longitudinal research is needed, as social media are rapidly expanding and evolving. New forms of social media may present unforeseeable risks for youth alcohol use and other off-line risk behaviours, but also opportunities for prevention. None.