In-browser mini IDE and Programming Language (opens in new tab)

The fail is on their side.

1. On my Windows and Mac machines I refuse to install the Silverlight plug-in (I haven't found a site that legitimately needs it yet). 2. On my Ubuntu machine (where I generally read HN), there is no Silverlight plug-in (and Moonlight isn't advanced enough even if I wanted it). I'm not sure Chrome for Linux could deal with anything but the Flash plug-in yet anyway.

HTML + javascript + asynchronous http request = open, interoperable web applications.

I'm actually working on something similar for a DSL used by my employer. We started with Javascript, but recently decided to port to Silverlight. I'm not entirely pleased with the decision, but within the context of the app, it makes sense--the DSL is used to generate screen flows on devices using WPF. By using Silverlight, we didn't have to define the existing WPF controls in Javascript in order to render the scripts from the IDE--we can just leverage (for the most part) the existing controls which are defined with XAML.

Personally, I don't particularly like developing via Silverlight--many of the tools required by VS2008 are buggy, and often there is precious little documentation as to how the tools work under the hood.

You mean yet another company trying to get me to learn yet another language they created specifically for their product? I'll pass. :P