Microsoft's Internet Explorer (IE10) boosted its user share last month by 53% as the company's enforced upgrade for Windows 7 continued to take effect.
IE10 increased its user share of all copies of IE from 10.8% to a record 16.5% in May, growing at a faster pace than the month before, according to metrics company Net Applications.
In relative terms, IE10 was the third-most-used browser of the five that Microsoft now supports, passing the 12-year-old IE6 for the first time.
IE10's climb has been brisk: As late as January, it had a mere 2.3% user share of all of IE. The increase was prompted by the automatic update from IE9 to IE10 on Windows 7 PCs, which began shortly after IE10's release on the popular platform in late February.
As in April, the bulk of IE10's gains apparently came at the expense of IE9, reinforcing the theory that they were due to the automatic upgrade. IE9's share of all copies of IE fell to 27.5%, a level it last saw in March 2012. In Net Applications' data, IE9 peaked in February 2013 at 38.8% of all copies of IE. It has been falling since.
Overall, IE remained flat with approximately 56% of the user share of all browsers, meaning that the rise in IE10 did not come from people switching brands.
IE8 also remained more or less flat, dipping just a few tenths of a percentage point to 41.1% of all copies of Internet Explorer. IE8's strong stake -- it's the most popular of Microsoft's browsers -- will remain intact, experts have said: IE8 is not only the most modern version available for the still-widely-used Windows XP, but it has also been adopted as the standard by many enterprises (free registration required) running mixed XP-Windows 7 networks.
Microsoft made some minor progress during May in stifling IE6, the 2001 browser it's been trying to strangle for years. IE6 was used by 10.8% of all those running Internet Explorer, a drop of three-tenths of a point from April.
Other browsers, including Mozilla's Firefox and Google's Chrome, grew and shrank in Net Applications' measurements, respectively, with Firefox ending May with a 20.6% user share -- up three-tenths of a point -- and Chrome accounting for 15.8%, a decline of more than six-tenths.
Chrome's precipitous fall in Net Application's eyes -- the firm has pegged Chrome's decrease at nearly 20% in the past 12 months -- has not been mirrored by rival StatCounter, an Irish analytics company that also publicly publishes browser data.
According to StatCounter, Chrome usage share for May was 41.4%, nearly triple Net Applications' accounting. StatCounter also had IE with a usage share of just 27.7%, or half that of Net Applications' measurement.
The gap between the two companies' numbers for Chrome and IE stems from their different ways of measuring share. Net Applications tallies unique visitors to the sites it monitors to provide a "user share," or an estimate of how many people run each browser. Meanwhile, StatCounter simply counts page views, producing a metric best described as "usage share."
Both companies could accurately describe Chrome's and IE's use, but that would require Chrome users, although smaller in number, to view significantly more pages on average than IE's followers.
IE10's time in the limelight may be brief if Microsoft crafts a version of IE11 for Windows 7. IE11 will make its first appearance in Windows 8.1, an update that will ship as a preview on June 26 and in final form later this year.
Microsoft has not said, however, whether IE11 will run on Windows 7.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, or subscribe to Gregg's RSS feed . His email address is email@example.com.
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