On the privacy front, the biggest new feature is InPrivate Browsing (which has been euphemistically referred to as the "porn mode"). InPrivate browsing lets users open a special window and then make sure that none of the information from that session is saved in the browser cache or history. When in an InPrivate browsing session, the address bar of the browser shows a special InPrivate icon.
To start an InPrivate browsing session, users can launch a special window from the Safety menu in IE 8. You can also launch an InPrivate session from any blank new tab or by hitting the Ctrl-Shift-p combo on the keyboard. I would have liked the option--found in similar privacy modes in browsers such as Google Chrome--to right-click on any link and launch it in a separate private browsing window.
One nice option within InPrivate browsing is InPrivate filtering. This feature can help prevent third-party sites from carrying user information over from site to site, and users can choose which sites they want to allow for this kind of data sharing.
Also on the privacy front, IE 8 increases the options within the Delete Browsing History function. Users now have more fine-grain control over what data they want to delete, including keeping data from some Websites while deleting it from others.
On the security side, Internet Explorer 8 continues to build on the capabilities added in IE 7 and in competing browsers to prevent users from travelling to malicious Websites and to keep malware from running through the browser.
The IE 8 SmartFilter is a service (which users can choose to turn off) that checks out sites before users surf to them. If a site is identified as one known to be a phishing site or to contain malware, IE 8 will display a warning page to the user before he or she travels there.
IE 8 also now puts the core domain name of a site being viewed in bold. This makes it easier to detect if a site is using a URL similar to, but different than, the one that the user expects to be surfing to.
Along with these obvious security features, IE 8 includes several under-the-covers features designed to stop scripting attacks, ActiveX exploits and rogue data execution. While these measures should improve security, users shouldn't expect the browser to be fully secure. As is the case with all new browsers, it is inevitable that there will be security problems with this new version of IE.
In IE 8, Microsoft has also made some stability improvements. One of the nicest of these is tab isolation, which brings down just a single tab when an unstable site is surfed to, rather than bringing down the entire browser. This feature worked well in tests, although I was a little frustrated that it kept trying to reload the offending site in the tab, essentially restarting the tab crash sequence until I hit the stop button.
On the standards front there is both good news and bad news.
IE 8 is easily the most standards-compliant Microsoft browser since IE 5, but it's the least standards-compliant of the newest generation of Web browsers. IE 8 received the lowest score of any of the newest browsers on the Acid3 standards test from the Web Standards Project.
Because of the potential incompatibilities between IE 8 and sites written to work with older versions of IE, the new Microsoft browser includes a compatibility view that can be enabled to view sites that don't work well in IE 8. In my tests of the late-beta, release-candidate and gold versions of IE 8, I had to use this view once a week on average. I've definitely run into more sites that have problems with IE 8 than I've run into with any other new browser. Luckily, the compatibility view fixed the problems with these sites.
In general, IE 8 has proven to be stable in frequent usage and hasn't appeared to be a resource hog.
As with any vendor offering a new browser, Microsoft claims IE 8 is the fastest browser available. Since I've given my opinion on these browser speed wars elsewhere, I'll just say that IE 8 appeared to be plenty fast for normal Web usage in my tests.
As one would expect from a new Microsoft browser, Internet Explorer 8 is currently available only for Windows XP and Vista. Those wanting to try out the new Microsoft browser can download it here.