It can be said that both progressive enhancement and graceful degradation try to do the same thing: keep our products useful to every user. Progressive enhancement is a more sophisticated and at the same time stable way of assuring that but it takes more time and effort. Graceful degradation can be used more easily as a patch for an already existing product; it means harder maintenance later on, but requires less initial work.
Read the outside article: Graceful degradation versus progressive enhancement
Level: Advanced

