This paper describes a pilot investigation into the use of the social networking site Facebook as a platform for persuasive applications. The application domain is behaviour change in domestic energy consumption and the study focuses on determining peoples' attitudes towards the hypothetical coupling of the consumer product Wattson, which can monitor domestic electricity usage, to a Facebook application termed Watts Up. The Facebook application presents visualisations of users' own electricity consumption as well as that of their friends. Users' attitudes towards this notion were accumulated and analysed using grounded theory. Some user indications revealed negative opinions about the concept based, for instance, around privacy and confusion; however the balance of opinion appeared to favour the underlying idea that revealing other people's energy usage data would lead to competition and peer influence to reduce energy consumption.