Adsense for mobile ads are presicely matched to the conten of your mobile webpage using the same targeting tecnology as adsense for content. Our crawlers scan the page to determine its content and thend automatically serve ads that are relevan to what your visitors see.
In order for google to properly target ads to your mobile website or crawlers, needs to be able to access your mobile webpage. The phone user agent use to crawl your site will contain the string "Mediapartners-Google", so please set up your web server to grant access to your mobile content any user agent that contains "Mediapartners-Google".
Please also be awake that Google will not be able crawl your webpage for ads targeting if you are restricting access to your mobile website to a specific set of IP address.
From: Adsense Support
Tuesday, March 18, 2008
Adsense; how are mobile ads target?
