The post is about creating desktop applications with the help of PHP. And No, we are not using PHP-GTK. You can now create desktop applications without learning a completely new programming language! That is with the help of a free and open source tool called "Titanium". Whats more you will use your existing CSS and Javascript and PHP knowledge.

They introduce the different parts of the Titanium platform - the Desktop SDK, Mobile SDK and Developer tools - as well as explaining what it takes to use them and what you'll need to download to follow along. They take you step-by-step through the process (complete with screenshots) of making a basic "currency converter" application using the Exchange API to to the heavy lifting.

If you're not familiar with Titanium, it's a development platform that allows you to build native desktop applications for Windows, Mac OS X, and Linux using the Web technologies we use on a daily basis: HTML, JavaScript, CSS, Python, Ruby, and now PHP. [...] Since it may still be a while before the next release of Titanium that includes PHP, I've decided to provide instructions here on how to build the SDK from the master branch and connect it to the Titanium Developer application

You'll need to download and install the latest developer tool from the Appcelerator site, a package with the development SDK in it. Change a few links around, add some symlinks and you should be all set.