Google AdWords

Google AdWords is an online paid advertising service that places advertising copy at the top, bottom, or beside, the list of search results Google displays for a particular search query. 

AdWords is the full featured advertising platform for large companies or advertisers to use advanced features.  Small businesses use AdWords Express.
The choice and placement of the ads is based in part on a proprietary determination of the relevance of the search query to the advertising copy. 

AdWords offers pay-per-click (PPC), that is, cost-per-click (CPC) advertising, cost-per-thousand-impressions or cost per mille (CPM) advertising, site-targeted advertising for text, banner, and rich-media ads, and remarketing. 

The AdWords program includes local, national, and international distribution. 

Google’s text advertisements are short, consisting of one headline of 25 characters, two additional text lines of 35 characters each, and a display URL of 35 characters.