Amazon.com has made a deal with the US Postal Service to deliver books on Sunday... This might pay off, and it might not. While I love my books, there is seldom a time when I can't wait for the usual Monday delivery. Is the prospect of a Sunday delivery really going to trigger more impulse buys? Hmmm... It's difficult to see how this will enhance Amazon's bottom line. But Jeff Bezos has proven that he usually knows what he's doing.