• by Wendy Davis  @wendyndavis, February 10, 2009

Handing a victory to online publisher WebMD, a New York judge has ruled that the term "visitors" in an online ad contract does not mean "unique visitors."

"The term 'visitors' is unambiguous," Judge Doris Ling-Cohan ruled. She added that if companies want guarantees of unique visitors, they must spell out that expectation in the contract.

WebMD sued RDA International last year, alleging that the agency did not pay for online ads it had purchased, according to court documents. The contracts between the companies called for RDA to pay about $450,000 for ads on the health company's site, according to the written court ruling.

WebMD had guaranteed more than 7 million impressions and at least 36,000 visitors to "WebMD Health Zone and WebMD-related condition centers driving to www.eucerin.com website," according to the court papers. The ad contract was for a 12-month period beginning in January of 2007, according to WebMD's complaint.

RDA argued that WebMD did not meet its obligations because it counted the same visitor more than once, according to the court's opinion. RDA estimated that WebMD only met "70-80% of its contractual promises," Ling-Cohan stated in her written ruling.

Ling-Cohan ruled in favor of WebMD, on the grounds that the ad contract didn't state that each visitor must be unique. "If defendant wished to be guaranteed 'unique visitors' to the site, it should have specified such in the agreement," she ruled. Ling-Cohan also noted that RDA didn't complain to WebMD while the contract was ongoing.

The pay-per-visitor component of the deal between WebMD and RDA appears to be highly unusual. One media buyer told Online Media Daily that any contract for "unique visitors" was likely to be problematic because cookie-based counting methods are flawed. "Anybody who would do a deal on unique visitors basis is not thinking clearly," the executive said. "As soon as someone deletes their cookies, they're no longer unique."

The decision was issued last month, but wasn't widely known until it surfaced last week on cyberlaw expert Eric Goldman's blog.

WebMD and RDA did not respond to requests for comment.