Pay per click (PPC), also called cost per click, is an internet advertising model used to direct traffic to websites, in which an advertiser pays a publisher when the ad is clicked.
Pay-per-click is commonly associated with search engines. 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, also known as "banner" ads, are shown on web sites with related content that have agreed to show ads and are typically not pay-per-click advertising.
However, websites can offer PPC ads. Websites that utilize PPC ads will display an advertisement when a keyword query matches an advertiser's keyword list, or when a content site displays relevant content. Such advertisements are called sponsored links or sponsored ads, and appear adjacent to, above, or beneath organic results on search engine results pages, or anywhere a web developer chooses on a content site.
The PPC advertising model is open to abuse through click fraud although Google and others have implemented automated systems to guard against abusive clicks by competitors or corrupt web developers.
Flat rate PPC: In the flat rate model, the advertiser and publisher agree upon a fixed amount that will be paid for each click. In many cases the publisher has a rate card that lists the pay-per-click (PPC) within different areas of their website or network.
These various amounts are often related to the content on pages, with content that generally attracts more valuable visitors having a higher PPC than content that attracts less valuable visitors. However, in many cases advertisers can negotiate lower rates, especially when committing to a long-term or high-value contract.
The flat-rate model is particularly common to comparison shopping engines, which typically publish rate cards.However, these rates are sometimes minimal, and advertisers can pay more for greater visibility. These sites are usually neatly compartmentalized into product or service categories, allowing a high degree of targeting by advertisers. In many cases, the entire core content of these sites is paid ads.
Bid based PPC: The advertiser signs a contract that allows them to compete against other advertisers in a private auction hosted by a publisher or, more commonly, an advertising network. Each advertiser informs the host of the maximum amount that he or she is willing to pay for a given ad spot (often based on a keyword), usually using online tools to do so. The auction plays out in an automated fashion every time a visitor triggers the ad spot.
When the ad spot is part of a search engine results page (SERP), the automated auction takes place whenever a search for the keyword that is being bid upon occurs. All bids for the keyword that target the searcher's geo-location, the day and time of the search, etc. are then compared and the winner determined. In situations where there are multiple ad spots, a common occurrence on SERPs, there can be multiple winners whose positions on the page are influenced by the amount each has bid.
The bid and Quality Score are used to give each advertise's advert an ad rank. The ad with the highest ad rank shows up first.
Advertisers pay for each click they receive, with the actual amount paid based on the amount bid. It is common practice amongst auction hosts to charge a winning bidder just slightly more (e.g. one penny) than the next highest bidder or the actual amount bid, whichever is lower.
To maximize success and achieve scale, automated bid management systems can be deployed. These systems can be used directly by the advertiser, though they are more commonly used by advertising agencies that offer PPC bid management as a service.
