Web Services is a technology used to allow computer systems to talk to each other over the internet while passing through firewalls. For example, if you install a program on your PC which uploads photographs to a website, there is a good chance the program will use Web Services to communicate with the web server as part of the process. The Web Services approach is popular with software developers because it is easy to use and reliable.

Web Services is also used extensively in systems integration, allowing transfer of information between server systems. In this area, Web Services is one of the cornerstones of the new SOA Architecture.

The ease of use of web services has also encouraged the development of online services which are accessed purely by web-services. The best examples of this are the Google Maps API, and Amazon’s online storage system S3.