Showcase optimized horizontal and vertical screens (video) for Windows 8

        Microsoft has demonstrated Windows 8 many times, but most of them are in landscape (widescreen) mode. This is because the browsing mode that ordinary users often use is horizontal, and horizontal browsing provides the best experience. In addition, early Windows 8 devices used a widescreen design, such as the Samsung tablet released at the BUILD conference, so that users can use the Snap function to view the application side by side.

However, this does not mean that Windows 8 ignores the portrait mode. Microsoft said that in some cases users still prefer to place the device vertically for viewing, such as when reading an e-book.

So Windows 8 was optimized for vertical screen browsing at the beginning of development. Developers can also use Visual Studio 11 and Expression Blend to test how their applications display in landscape and portrait modes at different screen sizes and resolutions.

David Washington, Senior Project Leader, Microsoft Windows User Experience Team, shows the horizontal and vertical screen view of Windows 8 in this video:
http: //v.youku.com/v_show/id_XMzE0NjI1NjIw.Html