Double Marginalization and Misplacement in Online Advertising*
研究了互补性网站如何选择广告策略，发现双重边际化导致广告过多，而错位导致广告在网站间分配不当，竞争可能缓解前者但加剧后者，引入微支付可消除错位但福利效果不确定。
Internet users often surf multiple websites as a bundle to fulfill their needs and ‘pay’ for the content by viewing ads. We study how such complementary websites choose advertising policies. Two forces distort the equilibrium away from the industry optimum and the efficient outcome. First, websites place too many ads (double marginalization). Second, given the total advertising volume at equilibrium, websites misallocate ads among themselves (misplacement). Competition in one market segment may eliminate double marginalization but exacerbate misplacement. Introducing micropayments removes misplacement, but the welfare consequences are ambiguous. Policymakers must thus be cautious when applying standard remedies to zero‐price markets.