Internet discussion forums and other forms of virtual social networking media are increasingly being used as sites of discursive practice. Quite apart from the research opportunities offered by conventional forms of Internet research (such as surveys and polls), discussion forums (alongside Web-logs and social networking sites) arguably provide new opportunities for social researchers to gather data in this very particular, but nonetheless popular cultural context. This paper explores the phenomenon through the large amount of textual data generated from an article on climate change and sustainable lifestyles in the Guardian newspaper. The discourses that emerged in reaction to this article provide valuable insights into the social construction of climate change and sustainable lifestyles, demonstrating conflicting arguments relating to the acceptance of climate change as a human-induced phenomenon, the reliability of data used to assert arguments concerning global warming and the contested views expressed over the value of adopting more sustainable lifestyles. Further, the paper argues that environmental social scientists need to become aware of the potential for analysing virtual discussion forums and social networking sites as valuable data sources for their research, recognising that these represent both cultural artefacts in their own right and alternative sites of discursive practice for anonymous and immediate everyday talk.