AdWords is Google’s branded text-based pay-per-click (PPC) advertising service.
Google’s advertisements are short, consisting of one title line and two content text lines. Advertisers specify the words that should trigger their ads and the maximum amount they are willing to pay per click. When a user searches Google’s search engine on www.google.com, ads for relevant words are shown as “sponsored link” on the right side of the screen, and sometimes above the main search results. The ordering of the paid listings depends on other advertisers’ bids (thus the system is classified as P4P) and the historical click-through rates of all ads shown for a given search.
All AdWords ads are eligible to be shown on www.google.com. Advertisers also have the option of enabling their ads to show on Google’s partner networks. The “search network” includes AOL search, Ask.com, and Netscape. Like www.google.com, these search engines show AdWords ads in response to user searches.
The “content network” shows AdWords ads on sites that are not search engines. Google automatically determines the subject of the pages and displays ads for which the advertiser has specified an interest in that subject. The ads show in boxes resembling banner ads, with the designation “Ads By Gooooooooooogle.” These content network sites are those that use AdSense, the other side of the Google advertising model.
AdWords is used by publishers who wish to bring traffic to their websites. The biggest competitors are Yahoo! Search Marketing (formerly Overture) and MSN’s soon-to-be-launched adCenter.
Most of Google’s revenue comes from AdWords.
The service has generated lawsuits in the area of trademark law and click fraud. 
Interacting with Adwords
The ads are displayed on the right hand side of the natural search results. The ads are pure text, and thus difficult to block. However, on external sites, they are hosted within an IFRAME (an HTML element), making them easy to remove with advertisement blockers.
The AdWords system was initially implemented on top of the MySQL database engine. After the system had been launched, management decided to use a commercial database (Oracle) instead. As is typical of applications simultaneously written and tuned for one database, and ported to another, the system became much slower, so eventually it was returned to MySQL ()
- Official Website
- Program Details and FAQ
- Adwords Lawsuits
- Google AdWords API
- Google Advertising Professionals aka GAP’s
- WhoisaGAP Helps you find out who is a Google Advertising Professional