PPC is the paid model of advertising on the search engines. The customer bids for keywords relevant to his target audience, for the advertisement (ads) that would appear when searches are made for those keywords. The ads appear on the sponsored area of the search page usually on the right, top or bottom of the search result page. Minimum bid amounts are called "Pay Per Click" amount and the customer pays only when clicks are made on the advt. The cost varies depending on the search engine and the level of competition for a particular keyword or keyphrase.
Although many PPC providers exist,the largest operators are :