TechCrunch covers Teambuy.com.cn, a "group buying" site based in China,
co-ordinate large numbers of consumers interested in buying the same products. People agree on a place and time to meet, then enter the store in crowds of up to 500 people at once. The crowds tell the store owners that they all want to buy, say a TV or a stereo, but everyone wants 10 to 30% off the retail price.
I remember Stewart Brand writing about this concept being applied to groups of people interested in buying the same model car in his book about the MIT Media Lab.