Problem Space addressed by WebServices

Web Services is probably not the first solution to such a problem. RMI, COM, CORBA, EDI, and ebXML also address the same problem space. So, what would make Web Services so special and different from the rest?

Web Services is based on the already existing and well-known HTTP protocol, and uses XML as the base language. This makes it a very developer-friendly service system. However, most of the above-mentioned technologies such as RMI, COM, and CORBA involve a whole learning curve. New technologies and languages have to be learnt to implement these services.

Also, Web Services is based on a set of standardized rules and specifications, making it more portable. This was not the case with the technologies mentioned earlier.