jigsaw is something like Plaxo in that its an on-line address books. It tracks companies, individuals, etc. and gives people a way to share their business contacts. Esther Dyson says it allows people to sell out their rolodex. She describes its essence this way:
The concept of Jigsaw is this: You take the contacts you have, and put them online. For each one you post, you get credits that you can use to buy other contacts. Or, you can simply open an account to buy contacts at $1 each.
