^{C H A P T E R}  1 Metadata, Resources, and the Resource Description Framework 1 T his book is about a technology that lets you tailor and filter content; create ad hoc portals; build profiles of users, information services, and objects; and gen- erally  give  the  user  a  richer,  custom-fit  experience.  It  is  about  how  you  can build metadata systems, especially systems that use profiles to create informa- tion services. Profiles, of course, are nothing but structured metadata descrip- tions, so they are not really remarkable in themselves. The remarkable thing happens when you start applying profiles to create services.   The Web is less than ten years old, and chat rooms are rife with complaints about the World Wide Wait. While there are some companies who deliver excel- lent service, most do a really bad job of it. The reason is not just that they do not  understand  what  adds  value,  it  is  also  a  consequence  of  the  enormous amount of data on the Web. You may well wonder what this has to do with wireless. But wireless access to Web information has proven to be not just the trigger for new types of devices and presentation formats, but for new types of information services as well. There is also a theoretical foundation: The more restricted the properties of a device, the less complicated grammars it can handle. And RDF is a very simple grammar. The way we use wireless devices is profoundly different from the way we use desktop computers, even though the information is the same. Building transac- tional services on top of the information requires that you know more about both  the  information  and  the  user  than  the  services  geared  toward  passive browsing. This is something we already see on the Web, but the real catalyst 69528_CH01Ix  4/6/2001 8:15 AM  Page 1