To help users cope with information overload, selective Dissemination of information (SDI) will increasingly become an important to olin wide area of information systems. In an SDI service, users post their long term queries, called profiles at some SDI servers and continuously receive new, filtered documents. To scale up with the volume of information and the size of users population, we need a distributed SDI service with multiple servers.In this paper I decribe the advent of XML as a standard for information exchange and the developmeat of query languages for XML data enables the development of more sophisticated filtering mechanisms that take structure information in to account.