Zombies and Grannies:

Why Attention Bonds May Not Cure Spam

Marshall van Alstyne’s recent contribution (“Curing Spam: Rights, Signals & Screens”) makes a strong case for aligning incentives in order to rectify the $50 billion unsolicited commercial email problem. While he (and his coauthors) have clearly identified the internal consistency of an attention-bond solution, the Coasean proposal that they outline appears to flounder on one key assumption: That it is possible to correctly allocate time rights and allow the relevant parties to bargain---either implicitly or explicitly---over a mutually-beneficial solution.

The problem with this assumption is that there is a significant amount of spam that is currently being sent via “zombie” computers: Internet-connected computers that have been compromised by viruses or trojans that perform the devilish deed of sending out spam, often without the owner’s knowledge. Should the owners of these zombie bots then be made liable for their contribution to the worldwide spam problem? Perhaps, as one could legitimately argue that the responsibility of maintaining a sound firewall lies on the owner of the machine. We do, after all, place the onus of policing private property on the owners of said goods. There is no reason why, legally, this should be a problem.

The problem, then, lies in the social implications of such a policy. Unlike cars or houses or land, the subtleties of security technology lie beyond the average user of the Internet. For good or ill, most Internet users with an always-on connection to the Net are average users who do not religiously plug security holes in their operating system, browser, or email reader. Even with push-based technology for keeping software up-to-date, the sheer number of non-professional Net users would suggest that, on any given day, a sufficient number of compromised machines are available for commandeering for malicious purposes.

Now imagine the social consequences of allowing these users to be charged for what is, undeniably, their individual security oversight. 70-year-old retirees, teenage high-schoolers, and otherwise honest, hardworking plumbers and farmers would be made the bear the cost of their lack of technological sophistry. ISPs will be blamed as the enforcers of such a draconian system, and, in order to maintain customer goodwill and company reputation, originating ISPs will be tempted to waive the attention bond charges, while recipient ISPs would agree on mutual write-offs. The solution becomes toothless, and the entire system unwinds. In practical terms, therefore, an attention-bond scheme is potentially time-inconsistent.

The scenario may turn out to be even worse. If a large number of average users perceive the risks of inadvertent charges due to unwitting attention bond payouts to be sufficiently high, they may choose to abandon the technology altogether. The Net would then regress to its halcyon days, utilized efficiently by a small cadre of academics and professionals, but absent the vast benefits that accrue from network externalities offered by a truly World Wide Web.

Utilizing economic incentives to deter bulk email is a fundamentally good idea, but unfortunately, attention bonds do not appear to be a solution that is socially feasible in the long run. Unless van Alstyne and his coauthors can conceive of a solution to the social challenges posed by zombie machines, the attention bond concept will face significant practical challenges once it becomes more widely implemented.


van Alstyne, Marshall W. (2007) “Curing Spam: Rights, Signals & Screens,” Economists’ Voice, 4(2): Art 2. Available at: http://www.bepress.com/ev/vol4/iss2/art4/.

This article appears in substantially shortened form in a 2007 issue of The Economists' Voice, as Zombies: Why Attention Bonds May Not Cure Spam.