In August 2010, Google Chrome exceeded 10% market share. Another milestone was achieved in September: Internet Explorer’s total usage dropped below 50% for the first time in over a decade.

There have been cheers throughout the web design and development community and the story has spread throughout the technical and mainstream press. However, it’s worth examining the StatCounter statistics in detail…

The ‘change’ column shows the absolute increase or decrease in market share. The ‘relative’ column indicates relative movements, i.e. 7.5% of IE6 users switched browser in the past month.

We can’t make too many assumptions from this data, but there’s one statistic reporters appear to have missed: IE8 usage has barely changed. The 0.02% drop is more than outweighed by the 0.09% gained by the IE9 beta release.

The most significant contributory factor for IE losses is migration from versions 6 and 7. Although a proportion of those users will have moved to IE8/9, a greater percentage has switched to an alternative such as Firefox or Chrome. There are several reasons why this has occurred:

• IE8 is a capable browser but there are plenty of better options for IE6/7 users.
• Good web applications are browser-agnostic or work on a variety of platforms. Legacy business applications are being updated and there’s less dependency on IE.
• Microsoft and all other major vendors are backing HTML5. The rendering differences between browsers is smaller than ever and it rarely matters which application you use.
• The majority of businesses use Windows XP and may have no intention of upgrading — especially during continued economic uncertainty. Yet IE9 is only available on Windows Vista/7. Why would a business continue to use an application which the vendor has (effectively) abandoned? It’s far cheaper and easier to install an alternative browser than upgrade the OS.

While we should be thankful for the drop in IE6/7 usage, 1 in 5 visitors continue to use the ancient browsers. Predictions of IE’s demise are premature and IE8 remains the world’s most-used browser.

It’s better news for the other vendors. Firefox, Safari and Opera all gained but Chrome remains the biggest winner. Google’s browser increases by nearly 1% every month and shows no sign of peaking. However, it’s about to face a stronger challenge from Firefox 4 and IE9.