Mozilla's Firefox increased its share of the browser market last month at the expense of Microsoft's Internet Explorer (IE) and other browsers, according to one set of statistics released this week.
But with another set showing that the opposite happened, with Firefox's share dropping in September, it's unclear which figures are correct.
The state of play in the ongoing battle between IE and Firefox is particularly important this month, because both Microsoft and Mozilla are nearly ready to release new versions of their browsers. In September, Mozilla launched Release Candidate 1 (RC1) of Firefox 2.0 but was beaten to the punch by Microsoft, which launched RC1 of IE7 a month earlier.
As organisations now have a chance to take a closer look at both browsers, the industry has been waiting to see which one holds the most promise and the early signs seem to indicate a split in opinion.
The worrying news for Microsoft comes in market share figures from Net Applications, one of the most widely used compilers of browser stats, which show Firefox's share reaching 12.4 percent in September, its highest total since the launch of version 1.0 of Firefox. Safari held onto its third-place spot, also with an increasing share at 3.5 percent.
These increases appeared to come at the expense of Microsoft, which saw IE remain way ahead of everybody else but with a slightly smaller share, 82.1 percent, down from 84.4 percent in June.
But not everybody agrees with that. According to the Web metrics company, OneStat, IE grew its market share of the browser market by 2.8 percent between July and September.
In the same period, Firefox's market share dropped 1.4 percent according to the same company, to 11.5 percent. On the face of it, it shows a clear difference of opinion between two sets of researchers, but the figures only really differ by around 1 percent — within the margin of error.
But some analysts do believe that Microsoft is seriously fighting back to increase its own dominant share. James Governor, of analysts Red Monk, said he was not surprised to see figures suggesting that Firefox's fast growth in market share was beginning to slow a little as Microsoft returned to growth.
"IE7 is a much better product again," Governor said. "It has some good new features, such as the way it works with RSS feeds, for example."
Microsoft is "taking the browser seriously again," he said. "They didn't for a while."
According to Governor, Firefox "needs to up its act again" and address some technical issues. "If you have a browser that has memory leaks all the time, it is very difficult to work with," Governor said.