When asked whether Microsoft will release an updated version of its Internet Explorer (IE) browser before Longhorn ships in 2006, Microsoft's pat answer is that it has no current plans to do so. IE is part of Windows, and that's that, according to the Microsoft party line.

But if you ask a slightly different question — whether Microsoft intends to add new features and functionality to IE without releasing a whole new standalone version — you'll get a different answer.

"We are looking at whether we can use the add-on mechanism (used by third-party software developers) to roll out new IE features" before Longhorn, said Gary Schare, director of product management with Microsoft's Windows client unit.

Schare did not volunteer any information on what kinds of enhancements or add-ons Microsoft might be considering. But IE users have been vocal in their demands for features such as tabbed browsing, built-in RSS reading capabilities and support for the most recent cascading style sheet standards.

Microsoft has published a number of IE-related application-programming interfaces to its Microsoft Developer Network site, to which it is encouraging third-party developers to write. The IE programming model includes support for XML and enhanced dynamic HTML, company officials said.

A number of third-party independent software vendors (ISVs) are developing to this platform, and are distributing all kinds of IE add-ons, ranging from blogging tools, to search tools, to RSS aggregators.

Microsoft recently aggregated this growing pool of IE add-ons and showcased it on its Windows Marketplace Web site. Windows Marketplace is Microsoft's one-stop online shop for Windows hardware, software and services from Microsoft and other vendors.

There are nine different third-party browsers listed on Windows Marketplace that use the rendering engine underneath, as does America Online with the current release of its AOL browser. Among them: Maxthon from the MyIE2 team; Net M@nager from Virtual Innovations; InnerX from InnerX; IESnap from Tonec; and the Avant browser from Anderson Che.

Microsoft's strategy for competing with these and non-IE browsers, like Mozilla's newly minted Firefox 1.0, is a three-pronged one, said Schare.

He said Microsoft will continue to issue security updates and hot fixes for its installed base of IE users; to evangelize to ISVs to get them to develop more IE add-ons; and to focus on building up the IE platform that will be integrated into Longhorn so that it is a great platform for customers and developers alike.

"There are no plans right now" to issue a separate standalone version of IE between now and when Longhorn ships, Schare reiterated.

The last standalone release of Internet Explorer issued by Microsoft was Internet Explorer 6.0 Service Pack 1, which the company shipped in the fall of 2002. Microsoft released IE 6.0 SP2 as an integrated part of Windows XP Service Pack 2 (SP2), which began shipping in August 2004..

With IE, Microsoft has cornered an estimated 93 percent of the browser market. Microsoft's share has declined slightly in recent months, primarily as the result of gains by Mozilla's Firefox.