What are Web services? If you ask 10 experts you’ll get 11 answers and many qualifiers.
Let’s start with an example instead: You want a stock ticker in your application or your browser? You can get that piece of programming as a Web service.
For the end user Web services run the gamut from simple programs like the stock ticker to the major components of a word processing application. Many vendors, such as Microsoft, hope to break up their huge applications and rent them out as Web services. You wouldn’t buy Microsoft Word; instead you would rent the pieces of Word you want to use.
From a consumer point of view, “Web services” are program components (to use object-oriented language, objects with encapsulated functionality) that are registered on Internet servers to be used as-is or in combination with Web applications.
The concept of gathering components from across the Internet to make up a program is not new. Technologies for doing what are often called distributed applications, such as CORBA and DCOM, have been around for years. These approaches, however, never fully succeeded. So what makes people think Web services will succeed?
In one word: standards.