The decoupling of producers and consumers in the publish/subscribe paradigm lends itself well to the support of mobile users who roam about the environment with intermittent network connectivity. This paper presents the first quantitative evaluation of publisher mobility in a distributed publish/subscribe system. Our results indicate that publisher mobility breaks a fundamental assumption of publish/subscribe systems and has a significant performance impact. We formalize publisher mobility algorithms for a distributed publish/subscribe system, and develop and evaluate optimizations to the mobile publisher algorithms.