Penny Black (research project)

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The Penny Black Project is a research project at Microsoft that tries to find effective and practical ways of fighting spam. Because deleting spams consumes a recipient's time, the idea is to make the sender of emails "pay" a certain amount for sending them. The currency or the mode of payment could be CPU cycles, Turing tests or memory cycles. Such a payment would limit spammers' ability to send out large quantities of emails quickly.

The project's name is derived from the Penny Black: the world's first adhesive stamp used for pre-paid postage.

[edit] See also

• Proof-of-work system
• Hashcash

[edit] External link

• An overview of the Penny Black Project from Microsoft