Many sites were built for IE7 and may not run properly with IE8, so IE8 has a Compatibility View that's designed to essentially trick a site into believing that you're running IE7.
When you visit a Web site built for IE7 that may not display properly in Internet Explorer 8, the browser is set to automatically switch to Compatibility View. You'll know when it happens -- a balloon tip appears briefly on the tab, telling you that the browser is displaying in Compatibility View.
In addition, an icon of a broken page lights up on the right-hand side of the address bar. That icon appears there, grayed out, when you are on a page that might be suitable for Compatibility View; to use the view, click the icon. Click again to get out of Compatibility View.
IE8 remembers that it needs to use Compatibility View on pages for which you've used that view before, so you won't have to click the icon each time you visit. In addition, you can opt out of the Compatibility View list if you want.
According to Microsoft, IE8 displays pages more quickly than IE7 and competing browsers. The company asserts that it focused on improvements in "real-world scenarios" such as how quickly it takes to load a page or start the browser, rather than optimizing the browser for specific benchmarks such as scripting performance.
I can only speak from personal experience -- IE8 feels zippier than IE7, but I haven't noticed a significant difference between it and Firefox.
Microsoft also claims that IE8 works better with Web 2.0 applications and AJAX because it better works with Forward and Back browser navigation buttons.
IE8 has a variety of enterprise-specific features. The company says it added more than 100 new Group Policy settings for IE8, such as whether IE8 should run in IE7 standards mode or IE8 standards mode, for configuring how the SmartScreen filter should work, and customizing search capabilities. System administrators can also slipstream IE8 into operating system images (but only with Vista or Windows server 2008 systems), so that IE8 need not be installed separately. Administrators also have more granular control of ActiveX controls.
Upgrading to IE8 from IE7 is a no-brainer -- the newest version of the browser makes browsing and searching much easier, has productivity-boosting features, is safer, and provides an overall superior experience.
That begs the question: Should you use IE8 or the current version of Firefox (which was at 3.07 as I wrote this)? For core browsing, IE is superior. It offers better tab handling, a better Search Box, and a slew of features that Firefox doesn't have, such as "porn mode," anti-malware protection, and Web Slices and Accelerators.
One thing it doesn't have, though, is an entire ecosystem of add-ins, and there doesn't appear to be such an ecosystem on the horizon. Web Slices and Accelerators are good technologies for delivering information, but not for changing the actual behavior of the browser itself. Moreover, there aren't many Accelerators and Web Slices available, and the selection of ones that are available sometimes leaves much to be desired.
So if you're a fan of add-ins and customizing the browser itself, Firefox is superior. But for the actual browsing experience, Internet Explorer has the upper hand -- for now.
This story, "Internet Explorer 8: A Complete Review " was originally published by Computerworld.