Desktop apps definitely have their own advantages over web apps like speed, ability to reach the filesystem, working in the background, notifications, etc.

However, for us (the web developers), it is a challenge to create one as they need  to be coded in a non-web programming language (yes, there are exceptions).

AppJS is an exciting resource that allows us to develop desktop apps using web technologies (HTML, CSS and JavaScript).

AppJS

The project uses Chromium as the core (so that the latest HTML5 APIs are supported) and Node.js as the backbone.

P.S. It is in the early stages of development, Linux and Windows ports are functional and Mac part is not available yet.