Google Adwords

It is system to assist you in marketing your products or services in the Google Search Engine, and its affiliate sites, via the use of a placed text ad that appears when people search for phrases related to your offering, this appears as a “sponsored link”.
The system is a “pay per click” system, this means you can dictate where your ad appears through bidding for a series of phrases, but you only pay the amount you have bid for if someone clicks on your ad as a result of a web search, i.e. pay per click!

ads.google.com/