Clay Shirky at WSJ.com – Does the Internet Make You Smarter?:

"We are living through a similar explosion of publishing capability today, where digital media link over a billion people into the same network. This linking together in turn lets us tap our cognitive surplus, the trillion hours a year of free time the educated population of the planet has to spend doing things they care about. In the 20th century, the bulk of that time was spent watching television, but our cognitive surplus is so enormous that diverting even a tiny fraction of time from consumption to participation can create enormous positive effects."

(Via Tim Bray.)