As mobile technologies continue to evolve, libraries seek sustainable ways to keep up with these changes and to best serve our users. Previous library mobile usability research has examined tasks users predict they might be likely to perform, but little is known about what users actually do on a mobile-optimized library site. This research used a combination of survey methodology and web analytics to examine what tasks users actually carry out on a library mobile site. The results indicate that users perform an array of passive and active tasks and do not want content choices to be limited on mobile devices. Responsive design is described as a long-term solution for addressing both designers and users� needs.