Top search ad placement is the coin of today's Internet services realm. An entire industry of search engine marketing companies have emerged to help advertisers optimize their ad campaigns to deliver high returns on investment, peddling a plethora of advertising strategies. Yet, very little is publicly known about the effectiveness of online search advertising, especially when trying to compare the various campaign strategies used by advertisers.
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Vattikonda et al. (2015) studied this question.
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