IE8 - tab groups

If you downloaded Internet Explorer 8, and wondering why some of the tabs sport different colors - this is one of the new features in IE8. It groups all the tabs opened from a single page (right click on a link and 'open in a new tab') with same color.
You might be doing research kind of work and google a word or phrase. From the results page you open few of them in new tabs. Now from each of these pages you might further open links in new tabs. All of these tabs open in single instance of IE (thought it spawns separate processes for individual tab page). Tab level color coding helps you with this kind of work.

One more, if you were using IE7 and used to saving the open tabs when closing browser instance, you will miss this feature in IE8. They instead did something similar to Firefox =) - that is if IE8 crashes, and you open IE8 again, it will ask you if you wanted to continue with earlier session. If you opt for it, all earlier tabs appear. Now you could be thinking that like in Firefox you will go to Taskbar and kill IE8 process so next time you can open the tab group. Well, you can do this - as long as you figure out and close the highlevel explorer.exe =)
The better alternative is for you to go to Favorites > Add to Favorites > Add current tabs to favorites.. > and give a folder name. Next time you open IE8, go to Favorites, find this folder and click the arrow against the folder name to open all of the tabs.

Update to the above point on 4/15:
When you open the browser next time, it gives you an option to "Reopen Last Browsing Session" below "What do you want to do next?" header. Clicking that opens up all previously closed tabs. =)