Google's Chrome edged past Microsoft's Internet Explorer (IE) last week to become the world's most widely used browser, according to data from an Irish metric firm.
Chrome's average usage share for the week of May 14-20 was 32.8%, said StatCounter, an analytics company that tracks browser and operating system trends. For the same week, IE's share was 31.9%.
Although Chrome has beaten IE in StatCounter's tally before -- a day here, another there, this was the first time that Google's browser took the top spot for an entire week.
Mozilla's Firefox placed third with a share of 25.5%, while Apple's Safari and Opera Software's Opera brought up the rear with 7.1% and 1.7%, respectively.
Chrome and IE are locked in a dead heat so far this month, separated by only five-hundredths of a percentage point through Sunday. The trend, however, is in Chrome's favor: It came within a whisker of beating IE the week of May 7-13, and early Monday it led Microsoft's browser 31.9% to 31.5%.
As recently as April, IE trounced Chrome by several percentage points. StatCounter pegged IE last month at 34.1%, Chrome at 31.2%.
But while Chrome may be on the verge of overtaking the long-time leader in StatCounter's eyes, other measurement companies still have IE far ahead of Google's 2008 upstart.
U.S.-based Net Applications, for example, tagged IE with a 54.1% share for April, compared to Chrome's 18.9% and Firefox's 20.2%. (By StatCounter's numbers, Chrome slipped past Firefox to take second place six months ago.)
The two metrics vendors use different counting techniques, which results in their widely-divergent results.
Net Applications weights its data by country to account for the relative paucity of information from nations such as China, and adjusts for Chrome's "pre-rendered" pages that users never actually see.
StatCounter does not weight its data by country, and only started to exclude Chrome's pre-rendered pages May 1.
The result is that Net Applications' numbers for IE are always larger than StatCounter's, primarily because Chinese users overwhelmingly run Microsoft's browser.
Not surprisingly, Microsoft has praised Net Applications' browser share reporting and dismissed StatCounter's as skewed.
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 email address is firstname.lastname@example.org.