Sencha has recently published a first look at the Internet Explorer 10 preview [via Sacha Storz]. This post summarizes the main points.

... what will be the differences between simply developing a web-based app for use by IE10 and developing a web app that gets delivered as a Win8 native app? The first difference is the resources that you’re allowed to access and how you’re allowed to access them. As a web-based app, you don’t get access to protected system resources such as camera, printers etc. To package your web app as a native app, you must create a permissions manifest file describing the protected resources that your app wants to access, and then submit your app to the (forthcoming) Windows app store. On submission, it will be checked for compliance with a battery of technical and policy tests.
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... what’s new in IE10? A huge number of new features, particularly in the area of UI elements and effects. The IE10 preview supports almost every visual HTML5 and CSS3 feature that’s been introduced in the last three years and several more besides. IE9 was already a serious step-up for Microsoft with capabilities such as hardware accelerated Canvas, but IE10 introduces much more ...
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Remarkably, particularly for developers trained to look out for Microsoft platform tie-ins, there are none on this list. Microsoft simply implemented the draft standards with no extensions or gotchas.
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In addition to substantial catchup on UI-related features, IE10 also pioneers some new technologies that haven’t made it into other browsers yet such as CSS Regions and positioned floats.
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With all the substantial catchup, there are a number of notable HTML5 technologies that haven’t appeared in IE10, and given Microsoft’s platform strategy, seem unlikely to ever show up there. First, WebGL is explicitly off the menu. To work with 3D graphics, it seems that web developers will have to use the JavaScript bindings to Windows Direct graphics APIs and distribute their apps only as Windows apps. Similarly, media capture and Device APIs are missing and given the thrust of the strategy, seem unlikely to show up anytime soon. These are the types of API’s that Microsoft wants you to consume via native bindings.

• A Windows 8 keynote review by a JavaScript programmer and Apple user

From http://www.2ality.com/2011/09/ie10-first-look.html