The social web represents a new arena for local, national and global conversations and will play an increasing role in the public understanding of science. This paper presents an analysis of the representations of nanotechnology on Twitter, analysing over 24,000 tweets in terms of web metrics, latent semantic and sentiment analysis. Results indicate that most active users on nanotechnology are distributed according to a power law distribution and that web metric indicators suggest little conversation on the topic. In terms of content, there is a remarkable similarity with previous studies of nanotechnology’s representations in other media outlets. Related to content is the sentiment analysis that indicates predominantly positively loaded words in the corpus. Negative sentiments mainly took the form of uncertainty and fear of the unknown rather than open hostility.