Installation for IE 7 includes two unusual requests. One, Microsoft asks that users briefly disable antivirus protection. Microsoft claims that there have been some conflicts between IE 7 installations and some antivirus engines, so to err on the safe side, the software giant asks that you disable your antivirus protection until the installation is complete. Neither Mozilla Firefox nor Opera make this request. Microsoft uses its own malicious-software removal tool during the installation of IE 7, and it is perhaps this tool that conflicts with some antivirus apps.

Another unusual request is that Microsoft asks users to reboot their computer after installation. Neither Opera nor Mozilla Firefox require a reboot. Unique to Internet Explorer 7 is an RSS feed engine that renders Web feeds as a readable page, and a reboot installs this engine in the system kernel. For the most part, we like the built-in RSS reader feature. Opera includes a newsgroups RSS reader, while Firefox allows you to associate RSS feeds with third-party readers.

Perhaps the biggest change within IE 7, aside from the overall interface redesign, is tabbed browsing, a feature already found within Firefox and Opera. Tabbed browsing allows you to open, view, and close multiple pages within one IE 7 session.

The tabs, which can be reordered, can also be previewed on a page with clickable thumbnail displays of each open tab. We prefer Opera, which provides native thumbnail views as your mouse hovers over each tab. The page preview available within IE 7, called Quick Tabs, requires an extra mouse click, which is an annoyance for the ergonomically minded.

Speaking of accessibility features, IE 7 includes zoom technology and new Clear-type page technology, which Microsoft claims renders page fonts as sharp and clear as those printed on a piece of paper. We find the IE 7 page zoom a bit clunky compared with that of Opera, which uses the scroll button on your mouse; Microsoft uses hot keys, preset sizes, and an option to render at a custom size. Even if you zoom to the maximum level of 400 percent, the Clear-text technology within IE 7 remains quite clear with fonts, although art and photos do become pixilated.

On the second tier of the redesigned IE 7 interface, in the upper left, Microsoft places its Favorites Center, accessible via the familiar star icon and a new Add to Favorites icon. The Favorites Center replaces the Favorites sidebar and includes tabs for RSS feeds and History.

Longtime users of IE 6 will react differently to the redesigned toolbar (top image)--some will like it, most will not. Microsoft claims users wanted the buttons and bars rearranged; in doing so, Microsoft deviates from the other popular Internet browsers on the market today. The back and forward buttons haven't moved; they're now compressed into the upper-left corner, and their individual drop-down menus have merge into one drop-down list. The address bar is now at the very top of the browser so that malicious spyware toolbars can't obscure or hijack it. Unfortunately, Microsoft has chosen the address bar to also display antiphishing and site certificate information, making the address bar sometimes a very busy place. Perhaps the worst new placement is the refresh button, which is now located immediately after the address bar. Even after using the beta for a few months, we still find it hard to remember where the refresh button is located.

RSS isn't treated lightly within IE 7; in fact, Microsoft built an entire RSS reader and bundled it in with the browser. Now when you click the RSS button, you'll see a listing of the feeds provided by a given Web site. Click the feed you want, and IE 7 displays the latest headlines and blurbs. Unlike IE 6, the page is readable (no more XML gibberish), with links to subscribe and to update the current feed.

Printing within IE 7 has also been enhanced; like Mozilla Firefox, pages within IE 7 now automatically shrink to fit on a printed page, sometimes resulting in microprinted text. You should always preview the page first so that you can customize the shrink if needed.

Like Mozilla Firefox and Opera, IE 7 has a built-in Internet search box in the top tier of the interface. If you install Internet Explorer on a clean system, the search box defaults to the little-used Windows Live.com site; however, if you upgrade and you already have a preference for, say, Google.com, Internet Explorer will respect your wishes and ask whether you want to continue using Google as your default search engine. If, on a clean system, you wish to change your preference from Windows Live.com to Google.com, IE 7 takes you to a search engine page where you can add additional search engines (oddly, Google is one of a limited few sites that do not include colorful logos, so look hard if that's the site you want). Once it's added, you still must click to make Google default, but the process is relatively painless. Unlike Firefox, IE 7 does not display search suggestions from your chosen search engine.

The Tools button appears to be IE 7's catch-all. From the drop-down menu, you can configure antiphishing, set pop-up blocking, manage add-ons, turn on or off toolbars, access the Sun Java Console, or choose from among other options, including Internet options.

While IE 7 offers Clear-type text enhancements, it still does not offer full Cascading Style Sheet 2.1 (CSS 2.1) standards compatibility and it has spotty support of XHTML 1.1, HTML 4.01, WML 2.0, ECMAScript, DOM 2, and SVG 1.1--standards supported by the W3C organization. Thus, IE 7 fails what is called the Acid2 Test, a test designed by the Web Standards Project to demonstrate complete standards compliance. So far, among the browsers reviewed by CNET, only Opera has passed the latest Acid2 Test, with Mozilla Firefox expected to comply shortly. As Web designers adopt these standards, some sites may begin to break as IE 7 falls farther behind the standard used by Web designers worldwide.

Security enhancements within IE 7 for Windows XP SP2 include increased malware protection by requiring you to opt-in when using ActiveX components (previously, ActiveX components installed automatically unless you changed the Internet options settings), along with an increased default Internet security level (medium-high), a new layer of certificate authentication, and antiphishing technology. Microsoft has added security protection to its new RSS reader as well, accepting only valid RSS feeds and not malware. There are also built-in code protections against Cross-Domain script attacks and malicious URL handling. However, much of the code used to create IE 7 has essentially remained unchanged from that of IE 6, so many of the non-ActiveX flaws now being discovered within IE 6 will likely affect IE 7.

IE 7 includes Microsoft's new antiphishing technology, designed to prevent users from providing personal data to fraudulent Web sites. Microsoft has touted its new technology (partnering with security vendors Cyveillance, InternetIdentity, MarkMonitor, and RSA Security's Cyota) as superior to others, yet in our own admittedly limited tests, we found that IE 7 consistently failed to catch phishing sites less than one hour old, although IE 7 caught all phishing sites known for at least one hour or more.

There are a lot of changes within IE 7, though not as many as we'd hoped and some that are merely cosmetic. Missing are innovative, cutting-edge features, such as search engine suggestions, live feeds within bookmarks, inline spell-checking, and session restore--features offered within Firefox 2--and thumbnail tab previews, desktop widgets, or voice (which can read Web pages aloud)--features offered by Opera 9. For more details, see our review.