the Claria software impaired the operation of Yahoo's services. For example, when a user with a Claria application installed used Yahoo Search, they received a standard set of Yahoo results with sponsored listings at the top supplied by Overture. The user would then receive a full-screen pop-under window from Search Scout. Since Search Scout uses Overture's paid listings as well, Claria's window has exactly the same listings as the Yahoo search results. Subsequently, Yahoo came out with the Yahoo Toolbar, which allows users to remove adware and spyware from their system. The toolbar affected the operation of Claria's software and may have put stress on the relationship between the two companies. See also Ad serving Google AdWords List of search engines Microsoft adCenter Pay per click Search engine marketing References External links Yahoo! Advertising Native Pay-per-click search engines