Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Collarity is a privately funded web services company based in Palo Alto, California that provides a recommendation system, social search, and online advertising services for web publishers. Collarity was co-founded in 2005 by Levy Cohen and Emil Ismalon based on the idea that data related to web user interactions with web content (sometimes referred to as passive filtering) could be used to improve search relevance, as an alternative to the historical emphasis on link analysis or explicit user feedback systems. The company was officially launched in November 2006.Collarity's technology is focused in the area of collaborative filtering attempting to leverage anonymous implicit web user data (e.g., articles/videos searched on or clicked), as opposed to explicit metadata such as tagging or rating, with the goal of creating an information value hierarchy. The intent is for this base of behavioral knowledge to ultimately make specific information more findable for specific online audience segments.