Internet Explorer 9 has a lot of cool new features. "Pinned sites" lets you create site-specific browsers on your Windows 7 desktop. Pinned sites by default recolor IE9's Aero glass-style interface based on the color schemes in the site's favicon, which is a neat little trick, and use the site's favicon as the Windows 7 taskbar icon.
If coded properly by the site's developers, a site can customize the jump list links, integrate player controls for streaming media sites such as Pandora, or have a counter display the number of unread e-mails in your Web mail account. Any site developer can implement the feature by using Microsoft's pinned site API. Check out this How To video to see how it's done.