In a recent article Google Lays Out Its Mobile User Experience Strategy (opens new window). In it they bring attention to something we don't often think about. Mobile users are either repetitive, bored, or urgent.

Repetitive

Someone checking for the same piece of information over and over again, like checking the same stock quotes or weather. Google uses cookies to help cater to mobile users who check and recheck the same data points.

Bored

Users who have time on their hands. People on trains or waiting in airports or sitting in cafes. Mobile users in this behavior group look a lot more like casual Web surfers, but mobile phones don't offer the robust user input of a desktop, so the applications have to be tailored.

Urgent

Request to find something specific fast, like the location of a bakery or directions to the airport. Since a lot of these questions are location-aware, Google tries to build location into the mobile versions of these queries.

Keeping these three user types in context can really help shape your project. If your site doesn't accomplish your users goals they likely won't come back.