See a developer preview of the new Internet Explorer 8. Some of the features that you will see include: 'Activities' and 'Webslices'. IE8 Activities allows you to do contextual search of text you highlighted on a website (for example if you highlight and address you can look it up on a map). IE8 Webslices gives you the ability to track a specific section of a site, similar to custom RSS feed.
IE8 has a few other features that are under the hood (such as greater compliance with web standards). Although they're not as visible the 'Activities' and 'Webslices'. Watch the video below more information.