Search engine keyword marketing practices are the subject of a lawsuit filed this week by WebMD against a major digital health services provider, Everyday Health, Inc., who is being accused of trademark infringement, false advertising, and unfair competition.

WebMD filed the lawsuit in U.S. District Court for the southern district of New York, against the provider, which served 43 million consumers and 500,000 health care providers last year. The digital health services provider says one-third of all American physicians used its services each month last year across the Web, mobile devices, video, and social media. WebMD seeks to permanently bar Everyday Health from engaging in the alleged marketing practices, and is seeking unspecified damages as well as legal costs. However, Everyday Health said in a statement that the lawsuit is without merit.

“Furthermore, the claims relate to only a small portion of the company's search engine marketing efforts — the campaigns referenced in the complaint relate to a very immaterial portion of Everyday Health's overall traffic and a very immaterial portion of the company's revenue,” Everyday Health said. “Everyday Health is confident that the lawsuit will not impact the way in which it operates its business going forward in any meaningful way.”

The company also said they intend to “vigorously defend” themselves against the suit. Everyday Health began in 2002 with the intention to create digital health content for major health brands in the brick-and-mortar world. By the end of the decade, the company had topped more than $100 million in annual revenue with such brand partnerships as the South Beach Diet.

Founded in 1996, WebMD is the leading provider of digital health content in the United States and elsewhere, however, with 156 million unique visitors per month in February.