1-800 Contacts, Inc. (1-800) (plaintiff) was a major retailer of contact lenses that registered the trademark “1800CONTACTS.” Lens.com (defendant) competed with 1-800 for internet sales of contact lenses. Lens.com had contracts with several affiliates that received commissions if they successfully made sales for Lens.com. Some of these affiliates purchased keywords from Google’s AdWords. Through AdWords, Google would use the keywords in a potential customer’s search to generate displays of sponsored links, called impressions. Lens.com’s affiliates purchased some keywords that were similar to 1-800’s mark. When 1-800 searched Google using terms identical or similar to its mark “1800CONTACTS,” some searches yielded impressions with links to Lens.com. However, the impressions themselves did not use 1-800’s trademark. 1-800 sued Lens.com for trademark infringement, alleging that Lens.com was creating initial-interest confusion. At trial, 1-800 presented evidence that one customer had canceled her Lens.com order once she realized that Lens.com was not 1-800. Additionally, 1-800 presented the results of a survey in which consumers were asked whether a Lens.com advertisement appeared to be affiliated with 1-800. The survey showed an average net consumer-confusion rate of 7.4 percent. The district court awarded summary judgment to Lens.com and dismissed 1-800’s infringement claim. The court reasoned that purchasing keywords using a protected mark could not, in and of itself, cause a likelihood of confusion unless the resulting impressions also used the protected mark. Additionally, the court excluded 1-800’s survey from evidence because the court had concerns about the survey’s methodology. 1-800 appealed, arguing, among other things, that its survey was improperly excluded.