What Improvements does WCF offers over its previous counterpart?

A lot of communication approaches exist in the .NET Framework 2.0 such
as ASP.NET Web Services, .NET Remoting, System.Messaging supporting
queued messaging through MSMQ, Web Services Enhancements (WSE) - an
extension to ASP.NET Web Services that supports WS-Security etc.

However, instead of requiring developers to use a different technology
with a different application programming interface for each kind of
communication, WCF provides a common approach and API.