Vanity Fair:
"The Simpsons is the bane of our existence," says Matt Stone, co-creator of South Park with Trey Parker. "They have done so many parodies, tackled so many subjects. 'Simpsons did it!' is a very familiar refrain in our writers' room. Trey and I are constantly having our little cartoon compared to the best show in the history of television, The Simpsons. Why can't we be compared to According to Jim? Or Sister, Sister?"
A very entertaining piece on The Simpsons, worthy of reading whether you're a fan or not.