I thought this was an interesting article by Yahoo's Jason Cole. Its probably one of the first times I've seen YPA written about in the mainstream media. He looks at the Chargers, who have a YPA difference of +1.5, an absolutely ridiculous number. Even more strange is this: "This has been an odd year statistically around the league. Among the eight division leaders, three of them (Jaguars, Falcons and Rams) have negative differentials."