Preston should remove the webbing from between his fingers before trying to install anything and definitely before writing another article. Holy stupid on steroids Batman. The guy doesn't even realize that when you unzip a compressed file you wind up with a directory of files and no further instruction:
How about on Linux --- specifically Unbuntu, the version most people see as the one best suited for mass use? Good luck, unless you are very familiar with the innards of the operating system. Looking to upgrade, I downloaded the proper file, then unpacked it. At that point, though, all I saw was a folder structure filled with files, and no install file, no hint, no advice on what to do next.
Then comes his revelation from a burning bush, probably the one flaming up from between his legs:
Mozilla offers advice on installing or upgrading to Linux, and it clearly says your best bet is to use a package manager. But when I checked the package manager on my version of Ubuntu, the upgrade to Firefox 3.6 wasn't yet available.
It's quite possible that an install for a particular OS isn't even built yet, or perhaps he just hasn't found it. In any case, if you're installing in Linux you better be prepared to roll your sleeves up and make the project yourself, or at least have the cognitive capacity to double-friggin-click the readme file for further instructions that, unfortunately, you do in fact have to read to understand

What a tool face banana rape master douche stain.