Just passing this info tidbit on I copied fr the e-mail:
The Windows 8 Developer Preview is a pre-beta version of Windows 8 for developers. The features and functionality in the prerelease software may not appear in the final version.. What was previewed at the BUILD 2011 conference in September blew almost everyone away - both at the consumer level as well as at the developer level. At the consumer level, everyone liked that the new, re-imagined Windows was not just a rip-off of iOS or Android, but a complete, cohesive experience - right from the start experience.
The first important change that has come is the introduction of a new Windows API called Windows Runtime (WinRT in short). WinRT caused a lot of confusion in the mind of developers till everything was clarified in the BUILD conference.
WinRT, for all practical purposes, replaces the older Win32 API which has been around since Windows was around. The WinRT API allows developers to create what are known as "Metro-style" apps. These are the new type of apps that run natively on the new Start screen, are fully multi-touch capable and run in full-screen mode.
Metro apps can be written in many different languages - C++, C#, VB or HTML5+CSS3+JavaScript. In the case of the .NET languages, WinRT loads the .NET 4.5 CLR - but only allows access to a sanitized subset of the same. This means although you can use the same language & syntax of a normal .NET application, you can only use a "clean" subset of this, not unlike Silverlight today. The design or front-end elements of a Metro app written with a .NET language is XAML. So, all your existing investments in learning Silverlight for desktop, browser or Windows Phone all remain intact.
The other option - using HTML5 and CSS3 with JavaScript code - also allows for rich Metro style content to be created quite easily. JavaScript is a first class citizen in this world and gets compiled to the same base as the rest of the WinRT apps. Using this option also allows you to scale out to the Web if you wish to or even use a different platform for your app.
....Ed
