A company that sells instructional videos and CD-ROMs has sued e-commerce giant Amazon for trademark infringement stemming from ads on Google.

The complaint, filed this week by Lakewood, Colo.-based Video Professor, alleges that Amazon uses the phrase "video professor" to trigger pay-per-click ads that direct people to a site that sells instructional CD-ROMS made by the company Professor Teaches.

Video Professor argues that the ads trick users into believing that its videos are being sold on the landing page. "It is highly likely that a user that googles the words 'Video Professor' searching for products sold by VPI (Video Professor, Inc.) might click on the Amazon.com link," the complaint alleges. "It is equally likely that once directed to the Amazon webpage having the name Video Professor at the top of the page, the user would purchase the CD-ROMs offered under the name 'Professor Teaches,' believing VPI to be the source of the products."

But a court might find Video Professor's argument problematic, because it relies on assumptions that might not be right, said cyberlaw expert Bennet Kelley. "There's a premise here that a consumer who types in video professor is looking for Video Professor," Kelley said. "But sometimes you type something in and want to see what else comes up."

An Amazon spokesperson declined to comment, stating that the company does not speak about pending litigation.

The complaint also alleges that the "first six products" listed on the landing page are Professor Teaches CD-ROMs, while an exhibit attached to the complaint shows that the seventh through ninth listings were for Video Professor programs. (On Thursday, the top listing on the Amazon.com landing page associated with "video professor" was for a Video Professor product.)

Because Amazon sells both Video Professor and Professor Teaches merchandise on the same landing page, the online retailer can argue that it's only using the "video professor" trademark to facilitate legitimate product placement -- or the placing of competitors' items near each other, said false advertising and trademark law expert Norman Simon, a partner with Kramer Levin Naftalis & Frankel.

In the last several years, a host of other companies have filed lawsuits over the use of trademarks to trigger search ads. In one closely watched case, Google prevailed in a lawsuit brought by insurance company Geico after a federal district court judge ruled that consumers weren't confused when they entered "Geico" as a search term and the results page included paid ads for Geico rivals. (Google and Geico reached a settlement about another portion of the case.)

But Google also settled a lawsuit brought by American Airlines after a judge declined to dismiss the lawsuit before trial.

Recently, a U.S. District Court judge in Texas ruled in Yahoo's favor in a search-related lawsuit brought by retailer Heartbrand Beef. There, a rival used the term "Akaushi" to trigger ads. Heartbrand unsuccessfully argued that it was the only U.S. seller of "Akaushi" beef -- or beef from cattle that were descended from a breed originally from Kumamoto, Japan -- and that Yahoo shouldn't have allowed any other companies to use the term as a keyword.

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