Why is Barnes and Noble cutting prices on the Nook Tablet?

Barnes & Noble announced today that it would cut the prices on both the Nook Tablet and the Nook Color e-reader. Beginning this week, the 16GB Nook Tablet will sell for $199, down from $249; the 8GB model, meanwhile, goes from $199 to $179. As for the Nook Color, which has always straddled the middle ground between tablet and plain old e-reader, expect to pay $149.