One reason for the sudden turn to crowd science is that it offers an imaginative answer to a central problem of 21st-century science: too much information. Oxford’s scholars had an overwhelming load of work given them, in the form of a desert trove. More often, though, scientists are themselves creating floods of data that they simply don’t have the hours to interpret. Every night, robotic telescopes relentlessly track the sky, pouring terabytes of images into hard drive farms. From biological labs come rivers of genetic code. And in many other fields — from high energy physics to environmental science — researchers are puzzling over how to handle the sudden embarrassment of riches.
That is from this excellent article on crowd-sourcing from the Boston Globe.
This TED video also presents an interesting perspective.