For a narrower, but revealing look at the current surge in sharing 2.0 ideas, try the recent book on collaborative consumption, "What's Mine is Yours"

http://www.collaborativeconsumpt...

This related and current question:

What are some sites that help people swap, lend or borrow physical items?

and this NYT article: http://www.nytimes.com/2010/12/2...

Relevant quote:

The phenomenon is rooted partly in environmental concerns about crowded
landfills and the energy consumed in manufacturing as well as a
mainstream embrace of recycling. Social media like Facebook lend momentum to the swaps as people join forces to trade, share or negotiate better deals from retailers.

“There’s a social piece here as well as a feel-good piece,” said Perry M. Lowe, who teaches marketing and social media at Bentley University in Waltham, Mass.

But experts say that the primary incentive remains economic. “It’s
really about shifting from consumption to the reality that we can’t
spend the way we spent before,” said John Gerzema, a consumer behavior
consultant in New York and co-author of a new book, “Spend Shift: How
the Post-Crisis Values Revolution Is Changing the Way We Buy, Sell and
Live.”