When Apple Inc.’s CEO announced recently that the Safari Internet browser would be available for Windows users for the first time, he said the move would increase Safari’s small market share.

“We think Windows users are going to be really impressed,” Steve Jobs said, arguing that because millions already use Apple’s iTunes music program on Windows machines, they would be willing to try Safari, too.

While only time will tell how the Apple browser will perform on Windows’ turf, more than 1 million copies of Safari for Windows were downloaded in the first 48 hours of the announcement in June, according to the senior director of Mac OS X product marketing at Apple, Brian Croll.

Safari is the latest arrival in a bitter Internet browser war whose main competitors are the once- dominant Internet Explorer and its main rival, Firefox. As different browsers compete for more market share, consumers are becoming the real winners, reaping benefits such as increased security and improved features, analysts say.

The most popular browser is Microsoft’s Internet Explorer, according to Net Applications, which published a market share report last month. It found that Internet Explorer has about 79% of the market, while about 14.4% use Firefox. Safari and Opera trail with about 4.6% and 1%, respectively.

This is the “second browser war,” a British technology journalist, Ben Hammersley, who coined the term in 2004, said. The first conflict took place in the late 1990s, when Internet Explorer wiped out Netscape’s market domination. At one point, more than 95% of people on the Internet used Internet Explorer.

The open-source browser Firefox arrived in 2004. Started by a nonprofit company, the Mozilla Foundation, it began luring people from Internet Explorer, which at that point was seen as having become stagnant in features and was marred by security problems.

Safari has also been available for several years, but only with devices using the Apple operating system. These consumers also have the option to use Internet Explorer and Firefox on the Apple platform.

While there is not a major difference between the browsers if they are properly updated, Firefox is the safest because Internet Explorer’s larger market share makes it a more attractive target for hackers, the author of several best-selling computer security books, Russell Dean Vines, the chief security adviser at Gotham Technology, said. He added that there are roughly 10 attacks on Internet Explorer for every one for Firefox.

As the different browsers compete for market share, they are adapting each other’s best features and coming up with new ones themselves. For example, Firefox was the first to popularize tabbed browsing, which allows users to open several Web sites at the same time in the same browser window, making navigation easier. Internet Explorer’s latest version, Internet Explorer 7, which came out in late 2006, uses the same concept.

Another browser, Opera, which has a small but loyal following, was the first to offer a feature that restores a Web browsing session when the computer freezes or crashes. Firefox’s latest version released last October, Firefox 2, now works on the same idea.

Standard features of Firefox 2 include a useful spell-check for all fill-in fields on the Web and a myriad of optional plug-ins designed to make Web browsing better.

Every Windows user has benefited from Firefox, including those who didn’t download it, because it forced Microsoft to improve Internet Explorer and compete for users, according to a technology blogger from Britain’s Guardian newspaper, Jack Schofield.

“But Mozilla does have a real problem, which is that the days of easy pickings are over,” he wrote. Microsoft’s Internet Explorer 7 “works well and so far hasn’t had the sort of security problems that afflicted” Internet Explorer 6, he said.

A 25-year-old New Yorker who works in television, Lanford Beard, said she likes Firefox better than Internet Explorer, but turns to Internet Explorer 7 for specific reasons, such as watching streaming video in formats that are not supported by Firefox 2. Due to so-called cookies, small identifying tags stored on browsers, Ms. Beard said she often uses Firefox 2 and Internet Explorer 7 at the same time, so she can log into two Web-based e-mail accounts provided by the same Internet company.

Internet Explorer’s flexibility comes with a price, Mr. Vines said. To interact better with Web sites, Internet Explorer relies on ActiveX technology, which if not controlled properly, can be a doorway for hackers.

Internet Explorer “has closed up a lot of the holes it had, and has been better at updating new vulnerabilities,” he said. “It’s still less secure than any of the other browsers, however.”