Most websites are simultaneously supported by display advertising and contextual advertising. In this paper, we develop an economic model to examine the profitability of these two ad types in both a monopolistic market and duopolistic market, identifying the influence of impression benefit and click benefit. We find that in the duopolistic market a rival channel's professional ability to enhance a visitor's impression is beneficial to the channel offering contextual advertising. We also find that the strength of a search engine is limited in the duopolistic market; therefore, acquisition becomes a prime strategy to reveal the value of contextual advertising.