ice Composition and Service Control can enable development, flexible control, and enrichment of a Telecom mashup service, using a combination of service modeling and rule-driven orches- tration of SOA capabilities. 1.4.1 Call-a-Cab Scenario The Call-a-Cab scenario is based on a mashup service called Business Finder [26], a next-generation, presence-enabled technology that leverages upon the underlying cellular infrastructure to provide efficient, on-demand, context-aware matching of customer requests to mobile vendors. Business Finder mashes up Location and Presence information, along with call control features, exposed by a Telecom opera- tor with third-party Google Maps service. Using Business Finder, one can search for a nearby and available vendor for a particular service. In the Call-a-Cab sce- nario, we consider Linda who is visiting Barcelona and wants to take a cab back to the airport. Using her GPRS-enabled phone, she logs on to the Business Finder portal and issues a search for a cab. Business Finder uses the location of Linda's mobile phone to render a Google map showing all cabs which are available and within a few miles of her location, along with a star-rating for the cabs (Figure 1.8a). Linda selects one of the cabbies, Chris, uses the Click-to-Call widget available as part of the mashup. This widget is enabled by IBM Telecom Web Services Server. Model diagram for the Call-a-Cab scenario is depicted in Figure 1.9. Figure 1.10 demonstrates the key functional elements of this setting, namely (a) Business Finder-a Telecom mashup service, (b) Telecom Web Services Server-an IBM middleware solution for delivering value-added Telco services such as 3PCC, Location, and SO on, (c) Service Composition plane to bind various offerings together, (d) SCL-for runtime control, mediation, and interaction management of 3PCC service that is invoked as part of the mashup, and (e) a charging platform integrated with SCL and used to apply different charging policies to Business Finder users. IBM WebSphere Telecom Web Se