Suchergebnisse

AbstractWe analyze the success of filtering as a solution to the spam problem when used alone or concurrently with sender pricing, receiver pricing, or both. We find that filtering alone may exacerbate the spam problem in terms of both the total number of spam message sent and the expected number of spam messages received, because it may cause the spammer to send multiple variants of his message to each customer in an attempt to evade the filter. Sender and receiver prices work as expected. The effectiveness of each instrument improves as the levels of other instruments are increased.

We examine a two-stage duopoly game in which firms advertise their existence to consumers in stage 1 and compete in prices in stage 2. Whenever the advertising technology generates positive overlap in customer bases, the equilibrium for the stage-1 game is asymmetric in that one firm chooses to remain small in comparison to its competitor. For a specific random advertising technology, we show that one firm will always be half as large as the other. No pure-strategy price equilibrium exists in the stage-2 game, and as long as there is some overlap in customer bases, the mixed-strategy price equilibrium does not converge to the Bertrand equilibrium.