Microsoft's Internet Explorer (IE) last month continued to shed users, losing the largest chunk of share since December 2010, Web measurement firm Net Applications reported Saturday.
During September, IE lost nine-tenths of a percentage point of share to slip to 54.4%, a record low for the browser. Last month's drop was the seventh straight decline and the most since last December, when IE fell by 1.1 points.
The beneficiaries of IE's slide were again Google's Chrome, which grew its share by seven-tenths of a point, and Apple's Safari, which gained four-tenths of a percentage point.
Chrome ended the month with a 16.2% share, while Safari accounted for 5% of all browsers used worldwide.
Microsoft, however, preferred to look on the bright side by again plugging the success of IE9 on Windows 7.
Roger Capriotti, the head of IE's marketing, used Net Applications' data to highlight the gains of IE9 -- the browser Microsoft launched last March -- by noting its 21% global share of browsers running on Windows 7, an increase of seven-tenths of a point. Microsoft's message has been consistent: It believes the future of IE is in the hands of its newest browser.
On Windows 7, IE9 is the second-most-popular browser, with a 21% share compared to IE8's leading 31.6%. In third and fourth place, respectively, were Firefox 6 and Chrome 13 with 13.9% and 13.1%.
Microsoft has never outlined an alternate strategy for stopping IE defections. While the focus on IE9 may pay off down the road -- perhaps when the huge numbers of Windows XP users finally retire that OS -- it's failed to slow defections. Since IE9's debut, Microsoft has lost 4 percentage points of share.
That was again illustrated last month: At the same time that IE9 gained eight-tenths of a point for a 8.7% share of the browsers running on all operating systems, the other editions collectively sloughed almost twice as much share. IE8, for instance, lost about two-tenths of a point, slipping to 29.9%, while IE7 and IE6 lost two-tenths of a point and 1.1 points, respectively.
IE6, which Microsoft has been trying to kill for more than two years, dropped by 1.1 points, the biggest decline since January 2011. Globally, IE6 -- a decade-old browser introduced just before the launch of Windows XP -- now accounts for an 8.6% share.
"And if you remove China's figures, IE6 only represents 3.5% usage share worldwide," said Capriotti in a Saturday blog.
Microsoft has been tracking the decline of IE6 on a deathwatch-style website for the last six months.
Chrome gained most of the share that IE lost, a trend in place since late 2009 when Mozilla Firefox's growth stalled. Firefox lost about one-tenth of a percentage point in September to end the month at 22.5%.
Firefox is in danger of losing its second-place spot to Chrome: If the two browsers keep to their pace over the last year, Chrome will overtake Firefox in June 2012. That's about six months later than projections based on data from rival metrics company StatCounter.
Chrome will crack the 20% mark in March 2012 if maintains its current tempo.
Apple's Safari was the only other browser besides Chrome to gain share in September. Using a boost in browsing by Mac machines, Safari exceeded 5% for the first time, said Net Applications.
Net Applications calculates browser usage share with data obtained from more than 160 million unique visitors who browse 40,000 Web sites that the company monitors for clients. More browser statistics can be found on the company's site.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His e-mail address is email@example.com.