Tim Bray is kind of a big deal in terms of the Web. He's been around technology longer than the Web, and he helped develop the important XML standard back in the '90s, and he contributed to the Architecture of the World Wide Web, Volume One.
Bray published a blog post about how important HTML5 will be to Web. In a nutshell, he said, not very.
"It's a good enough thing," he said, "to the extent it turns out to work. But nothing terribly important depends on it."
The goal of HTML5 is be able to more with HTML than can be done today, such as streaming video without a plugin.
"HTML5 promises to broaden the class of application problems you can solve with HTML," Bray said, "providing a good user experience while saving time and money. But that's all; it's not better because it's 'Web Technology', it's better because it's better."
But HTML5 isn't always better. Bray explains, "Right now, there are certain classes of applications, particularly on mobile devices, where you're going to get a better result by building a native app. Maybe even by building two or three native apps, for iPhone and Android and webOS. This is entirely orthogonal to the 'Webbiness' (or not) of the technologies."
In the end, he said, right now building Web applications that leverage the capabilities of HTML5 is "a major pain in the ass."
"HTML5 isn't better because it's a 'Web' technology. It might prove to be a user-experience and developer-productivity win. That'd be nice. But I'm neither holding my breath in anticipation nor losing sleep over delays and obstacles. The Web will do OK."
Bray is a Developer Advocate at Google.