From NBC to AOL, Nokia to Move Networks, the broad range of spotlight Silverlight applications attest to how much maturity the platform has gained since being launched last year.
Accessibility has been something of a weak spot in Silverlight 1.0; with only very basic support for alt tags and default actions. It hasn't been all bad, since this led developers to use Silverlight with "Plain Old Semantic HTML" in a progressive enhancement pattern -- which will continue to be useful in some scenarios going forward. But the range of options for accessible development increases substantially with Silverlight 2.
In this interview and demonstration, Mark Rideout explains the new accessibility enhancements in Silverlight 2; from support for controls and tabbing to support for (UI Automation) UIA.