What is the feature of silverlight 4? | WPF

Silverlight 4 is the current version at the time of writing and it introduced a number of new features, including :
Support for Google’s Chrome web browser
Access to the user’s web cam and microphone
Mousewheel input
Enhancements to existing controls, such as the DataGrid
New controls, such as the RichTextBox
Enhanced data binding support
Managed Extensibility Framework support
WCF RIA services