It is quite a dynamic, responsive design. They use
For example, shrink your browser window down, and you will see certain page elements appear or disappear depending on the window size.
This is common coding practise, and so not the sort of thing Google are looking out for as a spam signal.
Google's Matt Cutts on this: http://www.youtube.com/watch?v=EsW8E4dOtRY
The SEO Chat article you link to seems pretty hyperbolic and scare-mongering. For example, "hidden text is likely to get your site banned from the search engines instead of helping it!" - without giving any examples of a 'banned' site, and ignoring the fact most websites use it for genuine reasons.
I'd imagine more simply that cloaking has very little use in black-hat SEO nowadays because keyword spamming doesn't work (visible or invisible). No one is going to hide content which is about a different subject to their site, and writing "keyword keyword keyword keyword keyword keyword keyword keyword" in hidden text no longer cuts it.
The only exception to this I can think of is that hackers will often add hidden links to the pages of a site they have accessed for the Page Rank (and hiding the links from the webmasters, rather than Google).