PPC is an Internet Marketing model which is used to direct traffic to websites, where advertisers pay the publisher when the ad is clicked.
With search engines, advertisers normally bid on keyword phrases related to their target market. Content sites ordinarily charge a fixed price per click instead of using a bidding system. PPC "display" advertisements, also referred to as "banner" ads, are displayed on web sites or search engine results with related content that have agreed to show ads.
PPC implements the affiliate model, which provides purchase opportunities wherever people may be surfing, as opposed to the generalized portal, which attempts to drive a high volume of traffic to one site. It accomplishes this by offering financial incentives (as a percentage of revenue) to affiliated partner sites. The affiliates deliver purchase-point click-through to the merchant. It is a pay-for-performance model, which means that there is no cost to the merchant if an affiliate does not produce sales. Variations include banner exchange, pay-per-click, and revenue sharing programs.
Websites that utilize PPC ads display an advertisement when a keyword query matches an advertiser's keyword list, or when a content site displays relevant content. These types of advertisements are known as sponsored ads or sponsored links, and appear above, below, or adjacent to organic results on the results pages for search engines, or anywhere a web developer chooses on a content site.