CIO — Microsoft's Windows Internet Explorer (IE) continues to dominate the Web browser market, but Mozilla's Firefox browser made its largest gain in market share this year during the month of November--more than one full percentage point--according to new statistics on 160 million users from Web application and analytics firm Net Applications.

Apple's Safari browser also made a small gain in November, though Safari's market penetration overall has increased less than half of one percentage point throughout 2007. The Safari for Windows browser, which was released as a beta version last June, was used by less than one tenth of one percent of the users Net Applications measured.

Overall, Internet Explorer lost more than two and a half percentage points in market share since the start of the year, while Firefox saw a gain of more than two and a quarter percentage points. Net Applications says the majority of IE Web surfers are still employing version 6.0, even though the version 7.0, Microsoft's most recent upgrade, has been available for Windows XP for more than a year. More than 93 percent of Mozilla Firefox users are employing the most recent version of that browser, version 2.0.

Interestingly, total users Web browsing via iPhone topped the number of users browsing with all Windows Mobile devices combined, Net Applications says, though this fact is based on the operating system used, and therefore doesn't necessarily imply that Windows Mobile users were employing a Microsoft browser.

The company measures Web browser market share based on the software used by Web surfers who visit one of websites included within its customer base. Of this network of sites, 43 percent are commerce sites, 18 percent are corporate, 10 percent are "content" sites, like CIO.com, and 29 percent categorize themselves as "other," meaning government organizations, non-profits, search engine marketers, etc. Users included within the metrics may employ multiple browsers.

Browser Market Share for November 2007

• Microsoft Internet Explorer: 77.35 percent
  
• Firefox: 16.01 percent
  
• Safari: 5.14 percent
  
• Opera: 0.65 percent
  
• Netscape: 0.60 percent
  
• Other: 0.24 percent

Browser Version Market Share for November 2007

• Microsoft Internet Explorer 6.0: 40.24 percent
  
• Microsoft Internet Explorer 7.0: 36.84 percent
  
• Firefox 2.0: 14.97 percent
  
• Safari 41: 2.77 percent
  
• Safari 3.0: 1.85 percent
  
• Opera 9.x: 0.64 percent
  
• Firefox 1.5: 0.63 percent
  
• Other: 2.06 percent

Net Applications' 2007 trends in browser use, as well as trends in browser versions employed, are available on the company's website.