PPC

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 (typically a website owner) 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 or search engine results with related content that have agreed to show ads. This approach differs from the "pay per impression" methods used in television and newspaper advertising.

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

Among PPC providers, Google AdWords, Yahoo! Search Marketing, and Microsoft adCenter are the three largest network operators, and all three operate under a bid-based model

There are two primary models for determining cost per click: flat-rate and bid-based. In both cases the advertiser must consider the potential value of a click from a given source. This value is based on the type of individual the advertiser is expecting to receive as a visitor to his or her website, and what the advertiser can gain from that visit, usually revenue, both in the short term as well as in the long term.

Some PPC program providers are :
1. Google Ad words
2. Bidvertiser
3. AdGlobal360(Indian Company )
4. Yahoo Search Maketing
5. ABC search
6. Microsoft Ad Center
           
          Apart from these there are many small companies who pay you , these are many Advertising company who provides both PPC & PTC .