from Google’s Ten things
You can make money without doing evil.
Google is a business. The revenue we generate is derived from offering search technology to companies and from the sale of advertising displayed on our site and on other sites across the web. Hundreds of thousands of advertisers worldwide use AdWords to promote their products; hundreds of thousands of publishers take advantage of our AdSense program to deliver ads relevant to their site content. To ensure that we’re ultimately serving all our users (whether they are advertisers or not), we have a set of guiding principles for our advertising programs and practices:
We don’t allow ads to be displayed on our results pages unless they are relevant where they are shown. And we firmly believe that ads can provide useful information if, and only if, they are relevant to what you wish to find – so it‘s possible that certain searches won’t lead to any ads at all.
We believe that advertising can be effective without being flashy. We don‘t accept pop–up advertising, which interferes with your ability to see the content you’ve requested. We’ve found that text ads that are relevant to the person reading them draw much higher clickthrough rates than ads appearing randomly. Any advertiser, whether small or large, can take advantage of this highly targeted medium.
Advertising on Google is always clearly identified as a “Sponsored Link,” so it does not compromise the integrity of our search results. We never manipulate rankings to put our partners higher in our search results and no one can buy better PageRank. Our users trust our objectivity and no short-term gain could ever justify breaching that trust.