Jafar explains how theĀ Silverlight Toolkit uses Reactive Extensions. Jafar was one of the early adopters of Rx, in fact the Silverlight Toolkit was the first product to redistribute Rx.
Yesterday in part 1, Jafar showed a sample of how his team uses Rx in the product code
In part 2, Jafar shows how Rx is used to test Silverlight UI.