Believe me - it's a purely technical term amongst the XHTML purist. That's the way they have fun - stripping out the good 'ol CSS styles from a webpage and show off the raw XHTML code.
Why you might ask? By stripping all styles out, you can then look at your webpage in its most basic form to see if it's still readable and navigable.
The main idea behind Naked CSS is to promote Web Standards. By stripping out the facade, you can see if the raw code has good hierachical structure. Not only that, this will be the time you can see if you have managed to separate the content of your site from the presentation.
Web standards you say - who cares about that? Well, there are a few important reasons to this. One is basic human decency. With good web standards and web accessibility, you are helping users with visual impairment navigate your site with screen readers and braille devices. Although they might just make up a tiny percentage of your users, they're still an important part of your audience.
The other could fall into a fame or monetary gain category. By making sure your raw code presents the content efficiently (with good markup and presentation layer not interfering with content), search engines are more likely to index your site contents correctly. Good ranking in search engines = more visitors (perhaps more to click on those ads on your site to increase your revenue) or just a chance to form a cult.
There are also other aspects to good web standards; especially now with more and more people depending on communication devices like the iPhone, Palm and etc. By making sure a webpage adheres to web standards, a user who accesses the webpage either from his desktop or his mobile phone will get his information seamlessly. It might look different in those mediums, but the satisfaction level is still high since he's still able to complete his task.
