Microsoft's Internet Explorer 8 appears to be losing market share, even though the browser has been on the market for less than a week.

As of 8:00 am Monday, IE8 -- released Thursday -- held 1.86% of the browser market, down from a high of 2.59% on Sunday, according to market watcher Net Applications. The most likely reason for the decline is that early adopters of IE8 are switching back to the more familiar, and --at this point -- reliable Explorer 7 browser.

Explorer 8 includes a number of new tools, like a feature called Web Slices that lets users grab dynamic content such as stock quotes or auction results from third-party sites, that, while potentially useful, may take some time getting used to.

Additionally, Explorer 8 uses default support for some new Web publishing standards that aren't supported by a number of major Web publishers. As a result, some IE8 users have reported problems viewing some sites. "After downloading IE8 I cannot print any card from American Greetings. The message I get is, 'An error occurred during the operation,'" a user named Bob complained last week on Microsoft's IE8 forum.

Some IE8 adopters reported that even pages built with Microsoft's own Web publishing software, Microsoft Publisher, failed to render properly in the new browser. "I created my company's Web site using the MS Publisher 2007 template. After upgrading IE7 to IE8 my menu tabs and many important images no longer show," wrote a user named Phil Wheeler.

The news wasn't all bad for Microsoft, as some IE8 users said they were more than happy with the product.

Microsoft needs Explorer 8 to be a hit, as the company's Internet Explorer franchise has been losing ground to competitors. Explorer's overall share of the market has fallen from 75% to 67% in just the past 12 months, according to Net Applications, while competitors such as Apple's Safari and Mozilla's Firefox have gained ground.

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