Service-oriented architectures (SOA) is an emerging approach that addresses the requirements of loosely coupled, standards-based, and protocolindependent distributed computing. Typically business operations running in an SOA comprise a number of invocations of these different components, often in an event-driven or asynchronous fashion that reflects the underlying business process needs. To build an SOA a highly distributable communications and integration backbone is required. This functionality is provided by the Enterprise Service Bus (ESB) that is an integration platform that utilizes Web services standards to support a wide variety of communications patterns over multiple transport protocols and deliver value-added capabilities for SOA applications. This paper reviews technologies and approaches that unify the principles and concepts of SOA with those of event-based programing. The paper also focuses on the ESB and describes a range of functions that are designed to offer a manageable, standards-based SOA backbone that extends middleware functionality throughout by connecting heterogeneous components and systems and offers integration services. Finally, the paper proposes an approach to extend the conventional SOA to cater for essential ESB requirements that include capabilities such as service orchestration, "intelligent" routing, provisioning, integrity and security of message as well as service management. The layers in this extended SOA, in short xSOA, are used to classify research issues and current research activities.

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Virtual communities increasingly make use of standard Internet-enabled web services to support their collaborative activities. Such web services need to offer the right amount of functionality to meet community requirements. However, both requirements and enabling services are continuously in flux. A critical challenge therefore is that the community can efficiently ensure that web service changes are both technically feasible and socially acceptable.In this paper, we outline a selection approach for virtual communities that takes into account both the feasibility and the acceptability of web services. To this purpose, we adopt a semiotic view on the selection process, showing that for the adequate selection of web services three subprocesses are required: (1) syntactic discovery, (2) semantic matching, and (3) pragmatic interpretation. We then present a meta-model of web service selection support that is grounded in this view. This model can be used to detect gaps in web service selection support. This knowledge is essential for the construction of better selection support methodologies. We apply the meta-model to analyze a case on a courseware development community.

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