A large part of Google's annual turnover comes from its AdSense
advertising program. The Program enables website owners to drop in a piece of code to their pages that then serves advertisements provided by Google. It all works dynamically and the adverts that are displayed based on the content of the page. So if a website owner places the Google AdSense code on a page about holidays then holiday ads are delivered onto the page automatically by Google. when people click on one of the ads - the advertiser gets a visitor, Google can charge a rate for the clickthrough and the website owner who is serving the ad gets a share of this revenue. But there may be trouble ahead for Google ads, according to sources at CNET News, Yahoo! is planning a very similar service to challenge Google's. The two search giants have been up against each in the search advertising arena already but it is only now that Yahoo! seems poised to launch a monopoly-breaking attempt on Google's AdSense program. Do it too soon and you risk deterring visitors from staying on your website. Do it too late and you'll find that when you DO finally implement it people might not have seen it coming and they may leave your site in droves!. The best policy to adopt is, just like Google, to focus on RELEVANCE. Don't bombard your visitors with advertisements that are totally unrelated to their needs or interests or totally separate to the content you provide on your website.