A while back I sat down with Gary Price and talked about mobile search. One of the interesting discussions was about the decision to not include a search box on the initial screen of Ask's Mobile Search
What Ask found in their user testing is that users would immediately go to the search box and start trying to use it. While this sounds like it offers what the user wants, the fact is that accomplishing simple things like finding our the weather in San Francisco can take 70 keystrokes if you are on a mobile device without a QWERTY keyboard (for example entering the letter C requires you to hit the 2 button 3 times).
This does not sound like the pinnacle of usability does it? So Ask focused it's efforts on providing a streamlined interface that provides link based navigation to the functions of greatest interest to mobile users. This type of approach allows the user to get the information they are looking for much faster. It's an interesting lesson in making sure you understand the user's environment.