Service Oriented Architecture
Another architectural paradigm that's increasingly on the radar is service-oriented architecture (SOA). It's becoming a necessity for providers in the major industries (travel, finance, energy, and telecom) to offer a service-oriented approach. Services are designed so that customers can easily interact online with the provider, modifying or examining the service as required. SOA provides an approach to architecture design and development in which customers can easily and flexibly interact with a given service. This technique applies to the areas of airline reservation, telecom service providers, finance, and so forth.
Increasingly, customers want the ability to autonomously interact with the services to which they subscribe. For example, in online gaming, customer X may want to increase her bandwidth for a period of a few hours. Customer Y may want to check with his telecom provider to determine whether the contracted service-level agreement is being fulfilled. If the agreement has not been fulfilled, Customer Y may be due a rebate. Another common example is tracking shipping packages. All of these examples require some degree of SOA in the provider infrastructure.
SOA is often applied retroactively to an existing system, such as an airline reservation system. In this case, numerous best practices are emerging for the associated reengineering effort. 
An important aspect of SOA is the emerging area of the service delivery platform (SDP).  The SDP aims to overcome the problems of integrating disparate service elements, including access devices (such as mobile phones), servers, or other specialized back-end systems. The end user then gets the advantages of a fully integrated service platform, where delivery is not tied to the access devices.