Many-to-Many: Jigsaw Contact Market: "ts one thing to put your contact information in a social networking service. Its another thing to make connections explicit. But its an entirely different thing to make contact information literally tradeable.
The Jigsaw platform is basically a cross between the online marketplace of eBay and the social networking site of Friendster.com. Jigsaw users are able to buy, sell and trade business contact information. "