A keyword advertising system in which ads appear as "sponsored links" on the Google results pages as well as the results pages of Google's partners, such as AOL and Ask.com. The advertiser chooses keywords and a short one- or two-line text ad, which is displayed on the results pages when the ad keywords match up with the search keywords.
AdWords "Quality Score"
The order of ads is determined by several factors. One is the amount advertisers are willing to pay Google for a user to click their ad, and others are the relevance of the ad to the search and the historical click-through rate of the ad. In 2008, Google began to factor in the load time of the landing page. The overall quality score also influences an ad's position on the Google network, as well as affecting the calculation of a keyword's minimum bid.
Local and regional businesses can narrow down their targets to a specific radius of potential customers. AdWords was launched in 2000 and has been tweaked continually since. See Google AdSense
and keyword advertising