Difference between Asp.Net Web Services and WCF

Web service	WCF
It is hosted only in IIS	It is hosted in IIS, WAS(Windows activation service), Windows Service, Self-hosting
WebService attributes are used to define a web service	ServiceContract attributes are used to define a WCF service.
It supports only HTTP, HTTPS protocols.	It support various protocols like HTTP, HTTPS, TCP, Named Pipes etc.
It is slower than WCF	It is faster than web services
Hash Table cannot be serialized	Hash table cab be serialized
It support XML and MTOM message encoding	It support XML, MTOM, Binary message encoding
It does not support multi-threading.	It support multi-threading
It support one-way and request-response service operations.	It supports one-way, request-response and Duplex service operations.
It support XML serializer	It support DataContract serializer