The release of Firefox 1.0 this month appears to have sparked new activity in the Web browser market.

It seems to have prompted Microsoft to break the silence about Internet Explorer, and AOL is breathing more life into the Netscape brand with a preview of a new Firefox-based browser scheduled to be unveiled on 30 November.

Microsoft has no plans to release a new version of IE until the next version of Windows, code-named Longhorn, due out in 2006. Still, the company says it has the option to add features to IE by way of the browser's add-on technology, says Gary Schare, director of Windows product management at Microsoft.

"It is an option for the Internet Explorer team to add functionality in between releases. We do not have specific plans at this point to use it, but it is an option," Schare says. Microsoft's MSN group already uses the add-on mechanism for its MSN Toolbar.

Microsoft has not released a completely new version of IE in years. Windows XP users recently got a browser upgrade with SP2 (Service Pack 2). SP2 included features such as pop-up blocking and security enhancements, but those updates won't be made available for IE on earlier Microsoft operating systems, Microsoft has said.

While some people working on IE at Microsoft are maintaining the current version of the browser, most of the team members are focused on IE for Longhorn, Schare says. The Longhorn browser will include new features, improved security and privacy features, and better support for third-party developers, he says.

For end-user features, Microsoft is looking at better ways to manage favourites and tabbed browsing, a feature to improve the browsing experience by consolidating multiple web pages into a single window organised with tabs, Schare says. "Basically making IE a more functional and feature-rich browser," he says. Firefox and other browsers that compete with IE already offer tabbed browsing.

Meanwhile, AOL's browser unit Netscape Communications is preparing to preview a new browser based on Firefox. "It is based on Firefox, but will be Firefox Plus, it has got improvements beyond Firefox," AOL spokesperson Andrew Weinstein says.

The preview, an early-days, so-called alpha release, is due on 30 November. The new browser and a new email client will eventually replace the current Netscape offering, Weinstein says. He declines to detail product details.

AOL released Netscape 7.2 in August, but that product is based on Mozilla 1.7, a suite of products that includes a browser, email client, Internet Relay Chat client, and web page editor.

Riding a continued high, the Mozilla Foundation keeps counting Firefox downloads, which hit 4.7m last Friday morning, a spokesperson says.

The rise of Firefox, first introduced in February this year when Mozilla renamed its Firebird project, has been remarkable. The browser held 3 percent market share at the end of October, according to WebSideStory.

The Mozilla Suite, Netscape, and Firefox together held 6 percent of the market at the end of October, up from 3.5 percent in June. Though losing share, IE still dominated with 92.9 percent of the market, according to the San Diego web metrics company.

Firefox is the Mozilla Foundation's stand-alone browser. The Mozilla open-source project was started in early 1998 by Netscape, which was acquired later that year by AOL. Last year, the people behind Mozilla created a foundation, largely funded by a $2m pledge from AOL, to build, support and promote Mozilla products.