While people tend to contribute more to a virtual public good if they see others doing the same, this effect reverses if they become aware too many people are participating, according to research that I conducted over the summer. Public goods are things that many people share. They can be physical, such as highways, clean air and blood banks, or virtual, like a free online encyclopedia or mobile traffic app.
Click here for original story, People become less likely to contribute to a virtual public good like Wikipedia if they know many others are doing it
Source: Phys.org