With the launch of a major new version of virtually every major browser in the last few weeks, the discussion around how many downloads each one of them got is unavoidable and, as Microsoft’s senior director of its Internet Explorer business and marketing group, Ryan Gavin calls it, “a natural temptation.” In comparison with Mozilla, which just launched Firefox 4 last week, Microsoft’s download numbers don’t look great. Mozilla saw about twice as many downloads as IE9 during the first 24 hours of Firefox 4’s general availability (2.4 million vs. 7 million). According to Microsoft, however, there is a very good reason for this.

The difference between the way Microsoft releases its browser and the update mechanisms that Mozilla and Google have in place, though, means that it’s virtually impossible to draw any conclusions based on these 24-hour download numbers. Gavin rightly notes that both Mozilla and Google have automatic update systems in place that starts rolling the new browser version out to virtually all of their active users on the day it becomes available. Microsoft takes a very different and more conservative approach, though.

Firefox 4 Download Stats

Microsoft: “90% of IE9 Downloads Have Come From Non-IE9 RC and Beta Users”

Until now, only those users who downloaded IE9 directly were counted in Microsoft’s numbers. Indeed, Microsoft only turned on automatic updates for users who had beta and release candidate versions of IE9 installed yesterday. So far, according to Gavin, 90% of downloads of IE9 “have come from non-IE9 RC and Beta users.” IE9 still hasn’t been released for automatic updates through Windows Update, so comparing the early download numbers is, says Gavin “premature at best, and misleading at worst.”

While Gavin calls for “a thoughtful approach to measuring browser adoption,” he does take a slight swipe at the other browser vendors and, between the lines, accuses them of counting incomplete downloads in their numbers (“And remember, we report completed downloads – not attempted downloads where a user may hit a download button repeatedly but without fully downloading IE9.”).

Gavin also argues that his group is fully focused on Windows 7 and wants to give users on this operating system an “experience that will push the web forward.” Other vendors, he says, don’t have this “singular goal” of making their browser as good as it can be on Windows 7, as they focus on other operating systems, too. Some, of course, would argue that it’s a good thing to offer your browser for as many platforms as possible…

While I don’t fully agree with the overall sentiment of his argument, his call for pundits to wait for the point where IE9 becomes available through Windows Update is well taken (“Until that time, don’t get too wrapped up in the browser number gymnastics currently going on.”).