HTML5 for any device? yet?

Mark Zuckerberg made an widely recognized statement  on the usage of HTML5 for mobile devices:

When I’m introspective about the last few years I think the biggest mistake that we made, as a company, is betting too much on HTML5 as opposed to native… because it just wasn’t there. And it’s not that HTML5 is bad. I’m actually, on long-term, really excited about it. One of the things that’s interesting is we actually have more people on a daily basis using mobile Web Facebook than we have using our iOS or Android apps combined. So mobile Web is a big thing for us.

source: http://blog.tobie.me/post/31366970040/when-im-introspective-about-the-last-few-years-i
A more technical detailed feedback is provided here: http://lists.w3.org/Archives/Public/public-coremob/2012Sep/0021.html

This means two major things:

• HTML5 is not ready yet (that is no real news) for a simple replacement of native apps
• HTML5 is the major enabling technology to deploy feature rich content to the mobile web.

If you ever tried to create a productive web application using the HTML5 stack which should run on "all" common mobile devices you are aware that this is a pretty tough job and still requires to limit the functions to a small subset of functionality and as a result UI experience. In case you have to provide a feature rich application like Facebook you obviously have to workaround hundreds of issues and the result is still not sufficient for an individual user on one device.

A very helpful overview of the state of the different mobile browsers Facebook introduced ringmark a test suite (including results for most common mobile browsers) which shows which relevant API function is implemented on a particular mobile browser prioritized by different levels of importance.

The current state of the standards is published by W3C on a regular basis, latest release http://www.w3.org/Mobile/mobile-web-app-state/

What you see in the test results is that HTML5 can be used in case:
you want to deploy content driven application focus on online access and integration.

In any case you just have to start small, test and verify the behavior for your defined target audience. The HTML5 path is definitely the right path to follow but still requires lot of work from either the vendors and the standardization groups.