According to W3C's Web Services Activity Statement:

"The advent of XML [a simple and flexible computer language] makes it easier for systems in different environments to exchange information. The universality of XML makes it a very attractive way to communicate information between programs. Programmers can use different operating systems, programming languages, etc., and have their software communicate with each other in an interoperable manner..."

"The power of Web services, in addition to their great interoperability and extensibility thanks to the use of XML, is that they can then be combined in a loosely coupled way in order to achieve complex operations. Programs providing simple services can interact with each other in order to deliver sophisticated added-value services."

Web services are what are expected to allow billions of interconnected devices to communicate with each other intelligently in the relatively near future.