Monday, June 11, 2007

Competitive Emailing?

Over the last little while I've been noticing a strange signature on the bottom of emails I've received from people who have Yahoo! accounts.

New Yahoo! Mail is the ultimate force in competitive emailing. Find out more at the Yahoo! Mail Championships. Plus: play games and win prizes.

What? The abstract of a paper published last year titled “Competitive Emailing” by Martin-Herran, Guiomar; Rubel, Olivier, Zaccour Georges is as follows:

We consider an infinite-horizon differential game played by two direct marketers. Each player controls the number of emails sent to potential customers at each moment in time. There is a cost associated to the messages sent, as well as a potential reward. The latter is assumed to depend on the state variable defined as the level of the representative consumer's attention. Two features are included in the model, namely, marginal decreasing returns and bounded rationality. By the latter, we mean that the representative consumer has a limited capacity for processing the information received. The evolution of this capacity depends on its level, as well as on the emails sent by both players. This provides environmental flavour where, usually, one player's pollution emissions (here emails) also affect the payoff of the other player by damaging the common environment (here, the stock of consumer attention).

We characterize competitive equilibria for different scenarios based on each player's type, i.e., whether the player is a spammer or not. We define a spammer as a myopic player, that is, a player who cares only about short-term payoff and ignores the impact of her action on the state dynamics. In all scenarios, the game turns out to be of the linear-quadratic variety. Feedback Nash equilibria for the different scenarios are characterized and the equilibrium strategies and outcomes are compared. Finally, we analyze the game in normal form, where each player has the option of choosing between being a spammer or not, and we characterize Nash equilibria.

It turns out that competitive emailing is a model that "direct marketers" (read: spammers) can use to work out how to get as much advertising into you as possible before you get pissed off at them. That's even more confusing... What on earth does that have to do with playing games and winning prizes? And what are the Yahoo! Mail Championships? Is this a ploy to disguise the ad as something innocuous so that consumers don't realise Yahoo! is advertising to the world that it wants to sell their email addresses to spammers?

Oh Game Theory, you are such a double edged sword...

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