Crowdsourcing is all about involving people to share their concepts, ideas or creations in exchange for intrinsic rewards (recognition, awards) or extrinsic rewards(gifts, money, tangible items).
Examples of companies which execute crowdsourcing:
www.threadless.com
www.ideabounty.com
en.wikipedia.org

Crowdsourcing illustrates the power of the Internet – It builds communities, connects people, spreads messages, and taps into a global source of ideas and inspiration.