Web Services have Two Types of Uses

• Reusable application-components. 
• There are things applications need very often.So why make these over and over again?
• Web services can offer application-components like: currency conversion,weather reports, or even language translation as services. 
• Connect existing software. 
• Web services can help to solve the interoperability problem by giving different applications a way to link their data.
• With Web services you can exchange data between different applications and different platforms.