Silverlight facilitates the creation of rich web content and applications using a lightweight add-on that is friendly to both designers and developers.
ASP.NET automatically registers itself as the handler of ASHX resources. You can save yourself the editing of the metabase if you choose this extension for your custom handlers.
Udi discusses various patterns involved in creating MVC-based Smart Clients which communicate using asynchronous messaging and how to avoid threading problems there.
Embedding logic in the presentation layer might be a quick way to cobble together a simple web page interface, but for large-scale systems, separating the logic from the display with the MVP pattern is essential