A survey of  people participating in the Galaxy Zoo project provides a profile of the average citizen scientist  : What Makes Citizen Scientists Tick? – MIT Technology Review

The results are curious. Unsurprisingly, Galaxy Zoo volunteers are overwhelmingly male with 82.1per cent being men. There is also a particular over-abundance in the 50-60 age group. Overall, the volunteers have an average age of 43 and over 60 per cent come from the US and UK.

What is mildly surprising is their motivation for taking part. The survey asked volunteers to give their primary reason and this turned out not to be things like enjoying looking at pretty pictures of galaxies or the fun of it all. Instead, more than 40 per cent of volunteers say that the desire to contribute to science is their primary motivation.