A novel mobile social networking tool uses peer support to facilitate responsible drinking among young women. Focus group reports indicate that the tool's design is easy to use and its functionalities would help peers reduce risk during drinking sessions.Binge drinking by young adults is an increasing problem that results in a range of health and social harms.1 In most developed countries, drinking is considered an integral component to socializing, celebrating important events, and transitioning to adulthood. In Australia, for example, by the age of 18, approximately 50 percent of males and females drink at risky levels, but most perceive themselves as "social drinkers" and don't see their consumption pattern as problematic. In Europe, Denmark has the highest rate of binge drinking, with 60 percent of 15 to 16-yearolds reporting it; in the UK, the rate is 54 percent. Although women don't typically drink as heavily as men, they have equal or more problems than men if their drinking is immoderate. 5 Young women who binge drink are more likely to continue risky drinking patterns when pregnant 6 and frequent binge drinking during late adolescence increases the risk of depression later on.7 Women are also more vulnerable than men to the physical harms of alcohol and are at risk of sexual assault when intoxicated in public places. 8 These prominent issues-along with the observation that young women tend to look out for each other on social occasions to avoid potential harm to group members 9 -inspired us to target young women in designing a mobile tool to support drinking moderation.Most young people are reluctant to seek assistance in controlling their drinking due to stigma, embarrassment, and a desire to handle problems on their own.10 Governments and health authorities have attempted to transition young adults toward moderate drinking behavior via legislation, such as increased taxes on "ready mixed" drinks and advertising campaigns. However, these strategies have had only a limited impact on community-wide levels of drinking by young people.
11For an intervention strategy to be effective at the time and place it occurs, it must consider the context of consumption.12,13 To date, little research exists on the use of mobile technologies to moderate drinking. Research on Internet-based alcohol interventions for young people has typically focused on the provision of information and normative feedback, which has small but reliable effects, at least in the short term.14 However, these interventions aren't designed for use in the drinking context. Mobile phones provide a technological