The mobile revolution has been slow and steady. From a simple device used to call and receive it has become a high end computational device. The answer to Nokia’s tag line “Is this what computers have become?” is a very loud “yes, and maybe more”.

With the onset of the mobile revolution, many web services have also extended and integrated themselves with WAP. Search, the dominant service on the net has also extended it’s capability to the mobile user. Companies like Google, Yahoo and MSN are investing heavily to mark their dominance in the mobile search scramble. It is estimated that mobile search revenues would generate around $33.2 million dollars in 2007 and increase to around $ 102.3 million dollars in 2008(source: emarketer), an increase by more than three times.

While Microsoft provides search capabilities on all Windows Mobile platforms, Yahoo and Google provide search capabilities for a host of other service providers and mobile manufacturers such as O2, Telefonica, Vodafone, Motorola, and Nokia.

On first sight it appears that search capabilities across the mobile and the regular web would be the same. However a lot of factors differentiate a search application on a mobile from search on the regular web:

• Display inhibitions: When searching from a PC or a laptop, you generally have a 14-17’ screen interface. This allows you to have a view of all the results on one page. However the screen size of a mobile is very limited and hence the number of results displayed. Also each device’s display capabilities would be different. As such search engines would have to evaluate effective methods to identify documents with display capabilities for each device type.

• Relevancy: That brings us to the second differentiating factor. The relevancy of search results in a mobile search application needs to be high. In effect it translates into highly contextual and preferably local results. Relevancy implies that search engines would have to involve factors such as

o The location of the mobile user

o The profile of the user: This could be derived from call records, social networks etc.

• Language standards: Mobiles interfaces do not work on plain html and other web standards. The languages used for building or displaying content on mobiles are:

• XHTML: Extended HTML
• XHTML (MP): Extended HTML Mobile Profile
• WML: Wireless Markup Language
• CHTML: Compact HTML

XHTML (MP) is the standard that conforms to Wap2.0 standards. WML is slowly being phased out.

• Navigation: The keyboard of a mobile differs from the large QWERTY keyboard on PCs and Laptops. Even if a QWERTY keyboard has been provided on a mobile device, it would be quite small. As such navigation would be a major concern. Search Engines would need to evaluate each result being displayed to ensure that navigation is user friendly. This would obviously have a major impact on the indexing and the ranking algorithm employed for mobile search. Another important point to keep in mind is that mobiles don’t use the mouse, thereby presenting a major navigation inhibition. Also a page with a large number of images and scripts cannot be employed in a mobile search.

• User Behavior: The role of contextual and local search results has been understood. However the primary purpose of a mobile shouldn’t be ignored. The effectiveness of a search result would be enhanced by a ‘Click to call” or “Click to SMS” link.

One can easily infer that the results on mobile search would be different from those on the regular web. As such the optimization of web sites/pages would differ from regular SEO techniques.

A good starting point, I believe would be a deeper understanding of how Google and the other major search engines plan to index and rank pages.