This is a really important statistic for Microsoft. Given that its update strategy is very slow, it's great to see that the software giant has managed to build up hype for IE9. Although IE's market share is steadily declining every month, it is still the most popular browser, and IE8 is still the most popular browser version. As such, if Microsoft can make sure that IE9 adoption outpaces IE8, everyone on the Web will benefit.
Unfortunately, this will be very difficult to achieve given that IE9 is not available for Windows XP, which is still by far the most popular operating system version. IE9 may be being adopted rather quickly now, but that's just because users of newer operating systems are generally more tech-savvy and willing to try a new browser version.
As Microsoft has already said before, almost all of IE9's downloads so far have been user-initiated. Internet Explorer 9 was released on March 15, 2011. Two weeks later, on March 29, 2011, Microsoft started to push IE9 out via Windows Update, but only for existing IE9 Beta and IE9 RC users. The real test will come when the company flips the Windows Update switch for all users in late June.