When Darwin was developing his theories of evolution he read avidly in popular natural history magazines and sought out information from an army of almost 2000 correspondents. Such engagement with a wide public in the construction of science became increasingly difficult with the development of professional, and highly specialised science, but the emergence of ‘citizen science’ projects has suggested a new way forward. With the creation of vast data sets in contemporary science, there is a need for a new army of volunteers to help classify and analyse the information. The Zooniverse platform, started in 2007 with ‘Galaxy Zoo’, now has over one million participants who contribute to projects from astrophysics to climate science. Significant discoveries have already been made by these volunteers in the field of astronomy. Yet, the structures by which these volunteers might engage with professional science, and through which scientists themselves might draw upon their findings, are not clear, and researchers on the project have been turning to nineteenth-century models of communication to find ways of harnessing this huge popular interest in order to increase the rate of scientific progress.