There's little doubt that HTML5 is going to have a huge impact on our Web-surfing, as it's far more capable than previous standards to the point where entire plugins can be replaced. Plugins such as Flash, Silverlight and perhaps even the ever-vulnerable Java. While the Web remains rich with Flash-based content, whether it be video, games, or advertisements, Silverlight's implementation is rather minimal. In my personal experience, the only time I've ever needed it was when trying to watch some sports online. For avid movie-viewers, Netflix has no doubt been the leading reason for an install.
The folks at Netflix understand this well, and it considers that to be a downside. As stated in the linked blog post: "First, customers need to install the browser plugin on their computer prior to streaming video. For some customers, Netflix might be the only service they use which requires the Silverlight browser plugin. Second, some view browser plugins as a security and privacy risk and choose not to install them or use tools to disable them. Third, not all browsers support plugins (eg: Safari on iOS, Internet Explorer in Metro mode on Windows 8), so the ability to use them across a wide range of devices and browsers is becoming increasingly limited."
What's not explicitly mentioned is that it's not just browser-support that's the problem, but OS support. Because Silverlight support under Linux is virtually non-existent, for example, users of that OS have had to resort to extreme work-arounds to access the service. With Netflix's discussion of moving to HTML5, though, that sort of cross-platform roadblock could disappear.
While HTML5 is an open format, that doesn't mean that companies like Netflix wouldn't be able to implement DRM. In this particular case, "EME", or Encrypted Media Extensions, will be used for the purpose. It's a W3C standard that allows a content delivery system to encrypt the video stream - perfect for Netflix's purposes.
Also in the blog post, Netflix mentions that it's been working with Google to support the HTML5 video extensions in Chrome and also Chrome OS for Chromebooks. The future looks good here, although as a Linux user I find it unfortunate that the company didn't even mention the OS - despite Chrome OS being based on Linux. Regardless, if a Web browser has full HTML5 support, especially with the required extensions, the OS should never be the issue. This will be interesting to see play out.