XML and Web services are revolutioning the automatic management of distributed information, somewhat in the same way that HTML, Web browsers and search engines modified human access to world wide information. We argue in this paper that the combination of XML and Web services allows for a novel distributed data management paradigm, where the exchanged information mixes materialized and intensional, active, information. We illustrate the flexibility of this approach by presenting Active XML, a language that is based on embedding Web service calls in XML data. We focus on two particular issues, namely security and access control.