What is Fahrner Image Replacement technique, and why you should care

Russell Beattie talks about the huge increase in power behind the combination of XHTML+CSS (I agree), with links to an article In Defense of Fahrner Image Replacement (FIR is a CSS-based background image replacement technique, i didn't know that either!) by Vancouver's Dave Shea of www.mezzoblue.com fame.

A a demo of what is possible look at css Zen Garden a demonstration of what can be accomplished visually through CSS–based design, by selecting any style sheet from the list to load it into this page. Quite stunning