This page has been published end of 2010/March, and got over 20,000 views within 1 week, which is very very rare. This number must indicate there must be something that most web developers would be interested in:
Build Web application with HTML 5 (*"HTML5" doesn't need space between "HTML" and "5", actually)
I don't think I need to introduce HTML5 here. It's not just a next version of HTML specification, but could be also a platform of rich internet application, such as multimedia or local file access. Google had stopped developing "Google Gears" because it need other plugins. HTML5 would have a potential to replace them.
In above technical page, they introduce how to detect browser capabilities for HTML5 at first, and shows some sample code for future web application.
This is my personal impression, but HTML5 is still a "future" specification of Web, and sounds not so realistic at this time. But that is why we should learn and create web page now to make future collaboration easy.