Net Applications' May figure represents a record for the open-source browser, which resumed gains that had been interrupted in April when its share dropped slightly. The one-month increase was also the largest by Firefox since March 2007.
"Firefox is surging again, but their gains when reviewed over time aren't out of the ordinary," said Vizzaccaro. "Other than the stagnation Firefox experienced in mid-2007, their growth has been fairly consistent."
Vizzaccaro was referring to several months last summer when Mozilla's flagship browser slipped in market share, including May 2007 (down 0.9% from the previous month) and July (down 0.2%).
Although Vizzaccaro didn't pin all of Firefox's increase on a change last month to its update dialog, he did note the new approach. "Mozilla has implemented a change in Firefox 3.0 [Release Candidate 1] where the installation now has a checkbox that defaults to making Firefox your default browser," he explained. More>>