W3Schools posted their March data. For whatever reason, I’ve noticed that their latest month data is subject to change; its happened several times in the last few months that they will post a set of numbers and the next month revise it. But the trends are there to see; FF+IE keep a fairly stable market share ~90% (so no major third browser traction) with FF increasing quickly and IE7 increasing slowly, both at the expense of IE6. I note via the browser OS stats page that the number of Vista users has increased by 0.8%, in the last month but the number of IE7 users has only gone up by 0.4%; this reinforces the implication that pretty much all of the IE7 growth can be attributed to sales of Vista machines (that likely are replacing old XP ones), yet also again that at least half of Vista adopters are using Firefox (a rate higher than the ~third for XP users) at least among those who visit W3Schools.com anyway.
Update May 18: W3Schools released their April data… and also revised their March and February data again! Not sure if they changed their methodology or what, but I’ve contacted them to ask what’s up. In the mean time, be aware that the most recent month is (or couple of months are) subject to change…
Update May 21: They very nicely replied to my e-mail:
In the last months (actually, the last 10 months) the numbers has been changed somewhat as we have been developing and improving our statistics application.
When we change things in our application, we run statistics from previous months over again. That is why some of the earlier numbers are changed.
I am sorry for the confusion this may have caused.