Spotify's 35-year-old co-founder wrote an emotional letter to investors promising to make users 'emp

Spotify CEO Daniel Ek introduced himself to the world with a letter to potential investors. At roughly 1,300 words, Ek's letter touched upon the company's business potential. "We really do believe that we can improve the world, one song at a time," Ek wrote. Spotify is ditching underwriters, roadshows and even predetermined price ranges in its unorthodox "Direct IPO." But there's one tradition the music streaming company is sticking with: The founder's letter. The so-called...