An increasing number of organizations are turning to service-oriented architectures (SOAs) to consolidate and repurpose legacy applications and combine them with new applications. The convergence of Internet marketplaces and SOA is enhancing the growth of Web service ecosystems which is a logical collection of Web services whose exposure and access are subject to constraints characteristics of business service delivery. The service consumers in these ecosystems procure services through different distribution and delivery channels, outsourcing service delivery functions such as payment, authentication, and mediation to specialist intermediaries. The first beneficiaries of open procurement of web services are ventures that successfully overcame the dot-com burst. Application servers can serve as a technological analogy to Web service ecosystems where middleware functions facilitate interoperation of application components.