When Adele finally announced details of her long-awaited third album, “25,” in late October, the reaction was, unsurprisingly, rapturous. In an era when cultural saturation is a promotional strategy, ...

Getting your Trinity Audio player ready... This CD cover image released by Columbia Records shows, “25,” the latest release by Adele. The singer’s hotly anticipated album is out Friday, Nov. 20, 2015.

What should we think when an artist can make people buy almost 5 million copies of an album in two weeks? Or when nearly half of all music sales in one week are down to one person? The sales of ...