ASP.Net Blog: Why will Silverlight 4 be better for Business App Development?

RIA Services
WCF RIA Services (formerly .NET RIA Services) makes it quick and easy to create a Service layer that wraps your Data Access Layer - whether your DAL uses the Entity Framework, LINQ to SQL, or another technology. Note the name change from ".NET RIA Services" to "WCF RIA Services." As confusing as another name change is, this helps clarify that this new release is built on top of WCF - The communications channel from the Silverlight client to the RIA Domain Service is now a *.svc file - which means we can Add a Service reference to the service side, get WSDL, and customize WCF service settings.
Cider Support
VS2010 includes a XAML editor (Cider), supporting drag/drop forms design and data binding. In the past, developers needed to learn Blend to do basic GUI form design. Don't get me wrong, I love Blend : and we will still need to switch over to Blend to take advantage of Behaviors, States, Templating, animation, drawing, and other tasks. But many developers were turned off by the fact that Visual Studio had no WYSIWYG designer for XAML.
Data Sources Window
WCF RIA Services and VS2010 now support a rapid Drag/Drop design experience which allows you to quickly put together data-enabled Silverlight applications.

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