The title is highly misleading. H.264 is the most widespread codec by far thanks to Flash. In order to show WebM has having greater "share" the article's method

The title is highly misleading. H.264 is the most widespread codec by far thanks to Flash. In order to show WebM has having greater "share" the article's methodology excludes enablement via Flash. So IE8 and Firefox are considered "not H.264 enabled", even though the vast majority of video viewed by them is undoubtedly H.264. Now if you retitle it to only refer to native support for the HTML5 <video> tag that would be fair. But this still would have little impact on video codec choice. You want a codec that is widely supported and hardware accelerated, ideally. H.264 fits that bill through a combination of native HTML5 and fill-in Flash support, and that's exactly the best practice for video on the web today.