Google Webmaster Tools Promotion

Google displays a special ad if your query includes the site: operator, followed by a domain name: “Do you own Get indexing and ranking data from Google.

Many webmasters use the site: operator to check the number of pages indexed by Google, so it’s a good opportunity to promote Google Webmaster Tools.

This isn’t a regular AdWords ad, since it’s labeled as “Google promotion”. From what I know, it’s not even possible to create an AdWords campaign for all the searches that use the site: operator.