SAN FRANCISCO - The browser, that porthole onto the broad horizon of the Web, is about to get some fancy new window dressing.
Next month, after three years of development and six months of public testing, Mozilla, the insurgent browser developer that rose from the ashes of Netscape, will release Firefox 3.0. It will feature a few tricks that could change the way people organize and find the sites they visit most frequently.
Not to be outdone, Microsoft Corp. recently took the wraps off the first public test version of the latest edition of Internet Explorer, which is used by about 75 percent of computer owners, according to Net Applications, a market share tracking firm.
The finished version of Internet Explorer 8 could be released by the end of the year and is expected to have additional features.
Even Apple Inc., which once politely kept its Safari browser within the confines of its own devices, is making a somewhat controversial push to get it onto the computers of people who use Windows PCs.
In other words, the browser war - the skirmish that landed Microsoft in antitrust trouble in the 1990s - is heating up again.
"The typical browser for today's consumer doesn't look all that different than it did 10 years ago," said Larry Cheng, a partner at Fidelity Ventures, one of the firms that invested in Flock, a browser startup.
"That is an unsustainable trend that is the launching point for the second browser war," Cheng said, "which will not be won by monopolistic muscle but by innovation."
America Online, now AOL, which acquired Netscape, spun off the nonprofit Mozilla Foundation in 2003. Its Firefox browser soon inspired an open-source movement backed by computer enthusiasts. Early versions of Firefox introduced features like a built-in pop-up blocker to kill ads, and tabbed browsing, which lets users toggle between Web windows.
Firefox now has 170 million users around the world and an 18 percent share of the browser market, according to Net Applications. That is especially impressive given that most of its users have made the active choice to download the software, while Internet Explorer is installed on most PCs at the factory.
With tasks like e-mail and word processing now migrating from the PC to the Internet, analysts and industry players think the browser will soon become even more valuable and strategically important.
"People in the industry foresee a time in which for many people the only thing they'll need on a computer is a browser," said Mitch Kapor, the software pioneer who now sits on the board of the Mozilla Foundation and has created a startup, FoxMarks, that is developing a tool to synchronize bookmarks between computers. "The browser is just extraordinarily strategic."
That notion has helped to rekindle the browser wars and has resulted in the latest wave of innovation. Firefox 3.0, for example, runs more than twice as fast as the previous version while using less memory, Mozilla says.
The browser is also smarter and maintains three months of a user's browsing history to try to predict what site he or she may want to visit. Typing the word "football" into the browser, for example, quickly generates a list of all the sites visited with "football" in the name or description.
Firefox has named this new tool the "awesome bar" and says it could replace the need for people to maintain long and messy lists of bookmarks. It will also personalize the browser for an individual user.
"Sitting at somebody else's computer and using their browser is going to become a very awkward experience," said Mitchell Baker, chairwoman of the Mozilla Foundation.
Internet Explorer 8, from Microsoft, promises its own set of tricks. One new tool, Web slices, allows a user to bookmark a dynamic piece of a Web site, like an online auction or a sports score, and save it in the margin of the browser, where the user can watch as it changes.
Another new feature, called activities, allows users to highlight text on a page, click on it, then instantly send it to another site, like a mapping, e-mail or blogging service.
Apple's Safari Web browser has a little over 5 percent of the market, according to Net Applications, and subsists mostly on the loyalty of devoted Mac and iPhone owners.
But in March, deploying the kind of strategic jujitsu more commonly associated with Microsoft in the past, Apple began using the automatic update software that is packaged with its iTunes music player to deliver Safari onto the computers of people who use Windows. (Users had to specifically decline the Safari offer if they didn't want the browser to be downloaded to their computers.)
The tactic irked even Apple fans in the blogosphere, along with Apple's browser rivals. But it was at least partly successful: Net Applications reported that Apple's market share on Windows computers had tripled since March.
Shawn Hardin, chief executive of Flock, which is developing a browser that helps users share photos, videos and blog entries more easily, said consumers would ultimately benefit from the new browser battle.
"We are seeing choice in the browser market really emerge as a significant force for the first time in a while," Hardin said.