The 5 Leading Search Categories in 2006 were:

• Dining/Recreation
• Jokes/Riddles
• Ring Tones/Pictures
• News/Stock
• Weather Forecast

When optimising for mobile, the golden rules to remember are:

• Less is more  (ensure your content is uncluttered and clear to the end user)
• Page Size must be small (fast loading)
• Keep the design simple
• Use Style Sheets
• Use Div tags not Tables
• Optimise your images ? include Alt Text

Ensure you adhere to the W3C Guidelines as defined by the W3C?s Best Practice Working Group.