In this paper, we report results of an investigation into the effect of sponsored links on ecommerce information seeking on the Web. In this research, 56 participants each engaged in 6 ecommerce Web searching tasks using 60 organic and 30 sponsored Web links for each task. We extracted these tasks from the transaction log of an actual Web search engine, so these queries represent actual ecommerce searching information needs. In the study, we controlled for quality of the Web search engine results by switching organic and sponsored links on three of the six searching tasks for each participant. We counterbalanced the order of presentation among participants. We investigated the perceptions of sponsored links and the factors that influence this bias. Data included 2,453 interactions with links from result pages and 961 utterances evaluating these links. Findings include that there is a strong preference for organic links, a bias against sponsored results, and that more than 56% of the time, the title of the sponsored link was the determining factor in searcher perceived relevance. We discuss implications for sponsored links and paid search as a long-term business model.