Even with its shrinking share, IE remains the world's most popular browser: All versions of IE accounted for 52.8 percent of the browsers run during February, while Firefox and Chrome claimed 20.9 percent and 18.9 percent, respectively.
In another blog post, Capriotti made Microsoft's clearest defense yet for the numbers published by Net Applications, casting them in contrast to those from Irish metrics company StatCounter.
Net Applications, Capriotti noted Sunday, has long weighted its results by country -- using the estimates provided by the Central Intelligence Agency (CIA) for each nation's pool of online users -- and recently revised its data to account for Chrome's "pre-rendering," a trick that eliminates the sites that the browser downloads but may never show the user.
Both make Net Applications' figures a more accurate estimate of browser share, Capriotti said. In comparison, because StatCounter does not weight its data by online populations, it over-reports the shares of both Firefox and Chrome, and under-reports IE's.
StatCounter regularly shows IE with a smaller usage share than Net Applications: In February, for example, StatCounter had IE's total share at 35.8 percent, or about 17 percentage points lower than Net Applications.
As Microsoft has pointed out, IE9's share is tightly tied to Windows 7, in large part because the company decided not to support the decade-old Windows XP, which powered 49.4 percent of the PCs that went online last month. In that same period, Windows 7 ran 41.5 percent of all Windows PCs.
Microsoft's focus on newer operating systems will continue with IE10, which will run only on Windows 7 and the upcoming Windows 8. IE10 will not support the slowly declining Vista.
There is a bright spot for IE overall all, however.
In the past 90 days, IE's share has grown slightly, increasing by two-tenths of a percentage point. Chrome's share, meanwhile, dropped by about the same amount over the last two months.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld.