Web service is the way to publish application's function on web that can be accessible to the rest of the world.

Web services are the components that can be used by other applications

ASP.NET offers easy way to develop web services, just precede the functions with a special WebMethod ()> attribute in order them to work as Web Service.

Web services are discovered using UDDI directory services.

Web services are built on XML standard and use SOAP protocol that allows them to communicate across different platforms and programming languages.

Web services easily manage to work across corporate firewalls as they use HTTP protocol which is firewall friendly.

Web services platform elements are

SOAP (Simple Object Access Protocol)

UDDI (Universal Description, Discovery and Integration)

WSDL (Web Services Description Language)

The web services are built on internet standards that are not platform or language specific.

The .Net framework provides in-built classes to build and consume web services.

The components offered by web services are reusable.

The examples of web service components can be shipment tracking, translation utility, weather forecasting, sports scores etc.