Google AdSense™ automatically delivers ads targeted to your
website content. The more targeted your pages are for one or two
topics, the better the ads are likely to be. This free preview
utility will give you a sense of which ads would be placed on a
given page.
The ads shown on your pages will change over time as your
content changes or the inventory of Google ads changes. You
should check back here often to review which ads will be shown
when you're working on updating your pages.