Ignore the numbers for now, Gavin said earlier this week when he blasted early comparisons as "premature at best, and misleading at worst" because of the differences in the upgrade mechanisms of IE, Chrome and Firefox.
Microsoft plans to add IE9 to Windows Update sometime this month -- today he declined to set a date -- from where it will be offered to Vista and Windows 7 users. Mozilla has yet to offer Firefox 4 to customers running older versions of its browser, but will do that soon, a spokeswoman said Thursday.
The roll-out of IE9 via Windows Update and its Automatics Updates option will wrap up by the end of June, Gavin said today.
While the numbers may not provide an unambiguous case for the success of any of the newest browsers, one thing is clear: Microsoft has bet on IE9 and won't back away from that bet.
"We could have continued down the path we were on," said Gavin, again defending the decision to drop XP from the list of operating systems able to run IE9. "We could have added more features to IE, change the UI, blah, blah, blah. We could have made it work across XP, but that's not what's going to push the Web forward.
"We might have been more cautious [by creating a version of IE9 for XP] but you don't get quantum breakthroughs that way," Gavin said.
Microsoft's taking a risk with this strategy, said Al Hilwa, an analyst with IDC who covers browsers for the research firm. (IDC is owned by IDG, the parent company of Computerworld.)
"[XP] users will have to begin to use other browsers to handle [HTML5 content], and that is a risk because they may elect to stay on the other browser and never come back," said Hilwa in an e-mail reply to questions. "It is basic business that when you open such an opportunity for competitors, it is much harder to win them back. This is particularly true in the kind of fast moving disruptive market we are in and the high quality of the competitive browsers."
Gavin was confident that Microsoft could woo back Windows XP users when they eventually upgraded to Windows 7 or its successor.
"This is a temporal problem," said Gavin, referring to the time it will take XP to disappear. "Either we build a better experience or we don't. Pushing the Web forward, that's the best way to keep users."
Hilwa said that Microsoft made a tough decision to leave Windows XP behind, and that it will take time before anyone, including Microsoft, knows whether that bet paid off.
"I understand the agony on this," said Hilwa. "Microsoft made a complex cost-benefit analysis for supporting XP, and placed their bet. We will have to see how it plays out."
Net Applications calculates browser usage share with data obtained from the 160 million unique visitors who browse the 40,000 Web sites the company monitors for its clients. Its March browser statistics can be found on the Net Applications site.
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 e-mail address is gkeizer@computerworld.com.