I love talking about cognitive surplus...   Clay Shirky coined the term in his book Cognitive Surplus: How Technology Makes Consumers into Collaborators.  I'll provide a brief overview of the concept in this post and then elaborate on possibilites in follow-ups.

First, an awesome fact from the book:

The cumulative amount of volunteer time that has gone into creating the English version of Wikipedia (authoring, editing, discussing content): 100 million hours.

The total amount of TV commercials watched by Americans every weekend: 100 million hours.  Every weekend!

We, as a society, have a tremendous amount of free time.  Shirky calls this cognitive surlus and it represents a tremendous asset for us to harness... or let waste.  The internet provides new opportunities for individuals to spend their time creating and collaborating but for every Wikipedia editor or GitHub contributor, there are many more people posting pictures of cats with captions or harvesting virtual crops.  There is an immense potential to leverage our society's cognitive surplus to have a positive impact on the world... we need to start creating fun, engaging opportunities for participation.

Next up Cognitive Surplus: Retirees