Provided are a viral marketing service providing system for distributing advertisement costs for each marketer by analyzing a behavior of a content receiver, and a method therefor. For the viral marketing service for distributing advertisement costs for each marketer, the system comprises a content receiver behavior analyzing unit and a traffic quality index calculating unit, thereby precisely filtering abusing marketers (abusers), and thus can minimize damages to legitimate marketers with good intentions at the time of distributing predetermined advertisement costs. Also, the system can extract, by using a traffic quality index, high quality marketers who generate active behaviors on an advertiser's landing page or start a rumor of contents in a manner which aids in the advertising purpose of an advertiser, thereby distributing some of the advertisement costs paid by an advertiser to the marketers at a higher rate than other marketers.