title: Why do we need web-services? How different is it from normal web-applications?
body: <p>Just started with web-services so pardon me if my question sounds stupid.</p>
  
  <p>Why do we need web-services? How are they different from normal web applications?</p>
  
  <p>Two uses have been mentioned in many of the tutorials. One is the <em>communication between different machines/applications</em>, which sounds fine. But the next one is <em>to develop reusable application components</em>. My question is, do we need web services for that purpose?</p>
  
  <p>For Eg: A Currency converter can be implemented as a web service and it can be published on a url. But then, the same can be created as a web-application.  Where is the actual advantage of using web-services?</p>
  
  <p>Also as per some posts in SO, webservices should be used if no UI is involved and web-applications if a gui is required. Is the choice all that simple?</p>
  
  <p>Note: Here I'm referring to SOAP based web-service. RESTful ones might be different.</p>