Chicago-based SEM agency Resolution Media has been bought by Omnicom Group, becoming its first such acquisition, reports ClickZ. "The area of search engine marketing is increasingly important to our clients and requires highly specialized skills," Omnicom Media Group chairman and CEO Daryl Simm said in a statement. "We recognize that the growth of search engine marketing will help foster business opportunities and advance our digital leadership position in the marketplace."

Organic and Agency.com are among Omnicom's interactive agencies. Resolution, which provides paid search, SEO and strategic-planning services, will remain a separate entity within Omnicom's specialty media division. Financial terms of the deal weren't disclosed.

Resolution's clients include the Chicago Mercantile Exchange, the "Chicago Tribune," Bosch and Rand McNally.