define Tier III Search Engines

Definition:

Contextual distribution networks, through which marketers’ ads appear on pages within the PPC engine’s content network, triggered by user web site page views at the moment that contain the advertiser’s keyword in its content. Cost is usually through Cost-Per-Thousand-Impressions (CPM) charges, rather than Pay Per Click (PPC). As discussed in Fundamentals coursework, Google’s contextual distribution program is called AdSense; Yahoo!’s is called Content Match.