VS 2005 CTP Extensions for .NET Framework 3.0 (WCF & WPF) and Silverlight

Question

Forgive me if this has already been asked but the VS 2005 CTP Extensions for .NET Framework 3.0 (WCF & WPF) introduced the concept of a Browser based Xaml application.  Does Silverlight supersede this ? It appears that they are similar technologies.

Thanks

Steve