Mobile devices such as cell phones and personal digital assistants (PDAs) are becoming increasingly popular tools to access the Internet. Unfortunately, the experience of users attempting to access web pages with these mobile devices has been less than satisfactory because of their small display areas, slow communications links and low computing power. In this paper, we propose a trained scorer to estimate the mobile-friendliness scores of web pages, providing an indication of their suitability for mobile devices. These scores help mobile-friendly pages receive higher ranks in search results when mobile users seek information on the web. Our experiments show that the search results re-ranked by our mobile-friendliness scores increase mobile user satisfaction.