6.3 Exploitation of distributed legacy systems How will local content and service providers be able to have their services integrated in this agency? Legacy systems can be integrated and exploited by means of wrapper agents, which register their existence and services with a CRUMPET agency, and interact with the middle-agents. There are several options regarding which role such a wrapper agent can assume, e.g., whether it acts as one interface to all "hotel reservation services", or on behalf of one hotel chain, or even one single hotel. Another issue concerns the heterogeneous ontologies that are likely to be used by legacy systems. Ontology in this context is a description of the domain specific semantics that are associated with the terms that exist within the information sources. Service brokering, as characterised here, requires an ontology that allows matching and relating user requests, user interests, and service offers. The mediator agents and the user model are ontology-based and cover • the tourist domain (e.g., hotels, restaurants, sights) • service features (e.g., mode of payment, certain provider), • information request habits (e.g., preference for short information, dislike of animation). The latter two points require that services and the available information units be described by suitable metadata. Currently, this is not usually the case in internet-based services, but future development towards a "Semantic Net" (Berners-Lee, Hendler et al. 2001), (Maedche and Staab 2002) requires that tagging of content and services is carried out with reference to defined ontologies. The integration and exploitation of heterogeneous, location-based services cannot be tackled in due detail in this paper. There are still open issues, subject to ongoing design and development. As mentioned earlier in this paper, CRUMPET aims at goals that can only be achieved in a joint and continued effort of several projects.