Twitter canned its COO today and said it may not need one after all. Only 60 percent of Fortune 500 companies have one. So what’s the job of a COO? Plus, Amazon’s getting into music streaming now. It's gone down the video streaming route before too. Which raises the question, just what kind of company does it want to be? Also, the average size of a new single-family home in the U.S. continues its upward march… now eclipsing 2,300 square feet. Compare that to the average 40 years ago… just 1,500 square feet. We explain the economics behind the trend – there’s a much better margin in supersized homes.