Screenshot by Lance Whitney/CNET

Think of it as Microsoft's version of a good-news, bad-news joke. The good news: Its upcoming IE10 browser for Windows 8 will come in two flavors--one a streamlined, "Metro-style" program designed to resemble a smartphone or tablet app, the other a more standard desktop browser.

The bad news? Microsoft's upcoming IE10 browser for Windows 8 will come in two flavors--one a streamlined, "Metro-style" program designed to resemble a smartphone or tablet app, the other a more standard desktop browser.

In other words, everyone who wants to use IE10 will have to choose which flavor they want--and could even end up switching from one to the other mid-task. Microsoft is clearly thumbing the scales toward the Metro version of the browser, although it knows that some, possibly many, users will still prefer a more familiar and more fully fledged desktop version.

In the latest Building Windows 8 blog published yesterday, Rob Mauceri, group program manager for Internet Explorer, explained that the company designed its Metro browser to be fast, fluid, and simple.

The desktop version of Internet Explorer 10 provides the usual browser environment with optional menus, tabs, toolbars, and a host of other features. But in the Metro version, Microsoft has jettisoned most of those "manual" features to focus strictly on serving up the Web page itself.

"As people browse more 'chromelessly' on their phones, they've become accustomed to a more immersive and less manual browsing experience compared with the desktop," Mauceri said. "Metro style browsing offers you a full-screen, immersive site experience."

The first change Metro IE10 users will notice is that no menus, tabs, address bar, or other visual clues appear. Instead, the Web page takes up the full real estate of the browser. Right-clicking anywhere in the browser then reveals the address bar at the bottom and a space at the top where you can open a new page in a separate tab or close an existing page.

Clicking in the address bar displays a screen with Navigation tiles for frequently-used and pinned sites, so you can quickly open any site. Typing a URL in the address field displays sites from your History and Favorites; otherwise entering a new URL takes you to the new page.

The address bar includes the usual back and forward buttons (though instead of being next to each other, they're on opposite ends of the screen) and a refresh button. Another button lets you pin your current site to the Metro Start screen so you can access it without opening the browser. And one more button allows you to search for text on your current page or open the page in the desktop version of IE.

Hovering your mouse to the left or right of the screen displays arrow that can take you back or forward. The entire approach is designed to keep all features hidden until you need them.

Screenshot by Lance Whitney/CNET

I applaud Microsoft for trying something unique with its Metro browser. I like the clean screen that allows your current Web page to take center stage with no menus, tabs, or other items getting in the way. But there are also clear pitfalls to this approach.

In IE 9 I use a lot of Web sites set up as Favorites. They're organized alphabetically by folder so I know where to access each one. But the Metro approach doesn't lend itself to organization. You can pin your favorite sites to the Start screen. And links to frequently-used sites will pop up when you access the address bar.

But anyone who works with dozens of Web sites will quickly find this method unwieldy with no way to manage all of the sites you visit.

The Metro browser presents other obstacles.

There's no support for plug-ins, so surfing to Flash-enabled sites is out of the question. I use password manager RoboForm, which stores passwords for all my secure Web sites. That program uses a toolbar extension, which also is likely to be off limits to the Metro version of IE.

Accessing other options, such as printing a page or sharing it via e-mail, requires you to launch the separate Charms bar. That isn't as bad as it sounds, but it's not as convenient as running those tasks directly in the browser.

Finally, there's the whole question of trying to manage two flavors of the browser--one for Metro and one for the desktop. The two versions do share certain elements in common, such as a History list. But otherwise they behave as two separate applications.

Which one do you use? Do you stick with one or bounce back and forth between the two? Do the latter and you could find yourself opening the Metro app for a particular Web site only to realize you need the desktop version, which would defeat the whole concept of ease of use.

Yet even though IE10 feels and functions like two separate apps, Microsoft considers it one single app offering two different "experiences." That means it uses the same Favorites and History and the same underlying engine but provides two views--one for Metro and one for Desktop.

In Microsoft parlance, IE10 is neither a Metro app nor a desktop app but rather a third type known as a "Metro style enabled desktop browser." So technically, it is one single app that can take advantage of Live Tiles and other Metro features but still appear as a traditional desktop program.

Mozilla is adopting the same approach in buildling Firefox for Windows 8, aiming to create a single app with both Metro and desktop "experiences." The only limitation is that such a browser must be set up as the default, otherwise it functions strictly as a desktop app.

Google is also looking to build a version of Chrome for Windows 8, though it's not certain whether the search giant will create separate Metro and desktop apps or follow Microsoft's lead and develop a single browser for both environments.

No matter how it's named, IE10 in Windows 8 is still likely to confuse users accustomed to working with just a single instance of the browser. And the restriction that only the default browser can take full advantage of the new style will no doubt add to the confusion.

Microsoft is hoping people will gravitate toward the Metro IE version and sample the desktop flavor only when necessary. But the company is clearly taking a gamble with such an approach.

Updated 3/15 5:00 a.m. PST clarifying that IE10 will be a Metro style enabled desktop browser.