Paid Inclusion or Pay per click (PPC) (also called Cost per click) is an Internet advertising model used to direct traffic to websites, where advertisers pay the publisher ( Google Adwords, MSN adCenter , etc) when the ad is clicked. With search engines, advertisers typically bid on keyword phrases relevant to their target market. Content sites commonly charge a fixed price per click rather than use a bidding system. PPC "display" advertisements are shown on web sites with related content that have agreed to show ads.