Here's a really great article from The New York Times, about that greatest of all shows, The Simpsons (Who knew it took nine months to produce one show?) -Link-

Any other questions about the yellow ones can be found in the exhaustive Simpsons' Archive, too much Simpsons' related stuff here. -Link-

By the way, if you missed the link in the Simpsons article or haven't seen this before, there's a great site for tv fans who love to gripe about exactly when various shows went bad, or, as this site calls it "Jumped the shark" (a reference to the happy days episode when The Fonz jumped over a shark on water-skis, jumping the shark refers to that tangible moment in a show when it goes from "hot" to "not"). -Link-