A significant problem for managing information flow is the recipient attention devoted to processing spam email.
The identifying characteristics of pollution are present: recipients incur a cost (reading time, security risk) to determine whether the message is desired, and the sender generally has a better prior estimate of the message’s expected value. We developed an attention bond mechanism to provide incentives to reveal hidden information about potentially polluting email; AOL and Yahoo! recently announced they were implementing a related sender-pays system, but the community outcry illuminates a number of issues for ongoing research. We also developed a system to increase the benefits to advertisers of reaching customers through a different channel, thus reducing the desirability of paying to send spam to private inboxes.