From Understanding Progressive Enhancement, by Aaron Gustafson, October 7th, 2008 (http://alistapart.com/article/understandingprogressiveenhancement).

An old article but a clear explanation of moving from graceful degradation (creating for the latest browsers and leaving those using older browsers with meager content) to focusing on content while not neglecting style.

The view illustrated by the M&M peanut starts with what most websites are primarily about: content. Whether the site is about selling, collecting, convincing, educating or entertaining, it’s providing the viewers primarily content.

So when we’re creating sites we start with setting up the best html:

Start with your content peanut, marked up in rich, semantic (X)HTML. Coat that content with a layer of rich, creamy CSS. Finally, add JavaScript as the hard candy shell to make a wonderfully tasty treat (and keep it from melting in your hands).

This article is part of a three part series exploring the outer layers:

Progressive Enhancement with CSS (http://alistapart.com/article/progressiveenhancementwithcss)

Progressive Enhancement with Javascript
(http://alistapart.com/article/progressiveenhancementwithjavascript)