Mobile Search Engine Optimization: Developers Need To Know This
Google uses its Googlebot-Mobile to index mobile sites, and it uses particular bots and algorithms designed specifically for mobile devices, ranking results based on how the website renders on the type of phone which submitted the search query. Different devices often have different search results based on the evaluations that Google makes using different user agents. The goal for web developers is to create a design that will render well on all mobile devices.
Cascading Style Sheets (CSS) can be a mobile developer's best friend. By creating a mobile style sheet for your website, you can format your site's pages to they display your standard content on mobile devices without creating a special site for those devices.
Other mobile-centric techniques include using a mobile website map using Google's mobile sitemap tool. If you use multiple markup languages such as XHTML and WML, you need to create a sitemap for each language you use on the site. Google will then usually index your site using each sitemap that exists on your site.