In this research, we investigate the branding effect of an information technology system on the evaluation of system performance. Using Web search engines, we conducted a laboratory experiment measuring the effect of four search engine brands while controlling for the quality and presentation of search engine results. There was a 25 percent difference between the most highly and the lowest rated search engines based on average relevance ratings by users among the four search engines presenting identical results in both content and presentation. A positive brand is worth approximately fifteen percent in user perception of performance. Users place a high degree of trust in major search engines, but they are more engaged in the searching process when using lesser known search engines. It appears that branding affects overall Web search from various perspectives. We discuss implications for search engine marketing and the design of empirical studies measuring search engine performance.