AbstractWe describe a mobile agent application for distributed searching of the global Usenet network, implemented on top of the Ara mobile agent system. After short overviews of Ara and the Usenet, the application is presented in detail, beginning with some critical thoughts on mobile agent applications in general. The function and performance of the search application is then described, demonstrating the advantage of using mobile agents over an equivalent stationary implementation of the same application under certain conditions, and also discussing the limits of such conditions. This is followed by descriptions of the language to express the search queries and of the search algorithms employed. The application presentation closes with a critical discussion. The paper then concludes with some observations about mobile agent programming in general. Copyright © 2002 John Wiley & Sons, Ltd.