To deliver the best browsing across all Windows 8 devices, we re-imagined the architecture and experience of the web browser with Internet Explorer 10.
We built a new browsing experience in lockstep with Windows 8 to give you all the advantages that Metro style applications offer. We built that experience by extending IE’s underlying architecture to provide a fast, fully hardware accelerated browsing engine with strong security and support for HTML5 and other web standards.
The result in Windows 8 Consumer Preview is a Metro style web experience. IE10 is designed to make website interaction fast and fluid for touch as well as for heavy mouse and keyboard use. With IE10, websites participate in the Metro style experience in Windows 8, including the Start screen, charms, snap, and more. IE10 also provides the best protection from malicious software on the web while providing real control over your online privacy.
Web browsing in Windows 8 Consumer Preview with IE10 - Building Windows 8 - Site Home - MSDN Blogs
More on Windows 8 and IE 10 Metro revealed - Neowin.net