Data™ for Silverlight is an implementation of the standard DataSet, DataTable, and DataView classes familiar to Windows Forms and ASP.NET developers.
Reusable Business Logic
Data for Silverlight allows you to work with data in Silverlight applications in the same manner and with the same code as in Windows Forms. You can create a data library encapsulating your data and business logic and use it both in Silverlight applications and Windows Forms.