gregtyree.com

Stumbled on this concept that is now a few months old but still very interesting.  This reminds me of conversations we have had each time a redesign or new service is discussed.

Graceful degradation prioritizes presentation, and permits less widely-used browsers to receive less (and give less to the user). Progressive enhancement puts content at the center, and allows most browsers to receive more (and show more to the user). While close in meaning, progressive enhancement is a healthier and more forward-looking approach. Progressive enhancement is a core concept of Graded Browser Support.

For our family of sites we have loosely followed a similar model, although never quite classifying it as well as Yahoo has done.