The trend toward using Web technologies for application development, even outside of the Web browser, is here to stay. The recent revelation that Windows 8 will have provisions for writing apps using the HTML5 technologies merely cements this shift in the development world. So the question is: How are you going to deal with it?
HTML5 changes the game by adding support for things like video streaming, multithreaded and asynchronous processing (via the “Web Workers” message passing system), direct communications through sockets, and more. While the idea that a document format standard has these capabilities may be horrifying to some (including myself), this is the direction that HTML is headed in, and it has backing from Apple, Microsoft, Google, Mozilla, Adobe, and more. In addition, the various frameworks out there make it very easy to directly connect Web applications to backend Web services. As a result, HTML5 is now as capable as technologies like Silverlight, Flash, Flex/AIR, and JavaFX for many tasks (though there are still some things that those technologies do better).