Apple was quick to crow that its fledgling music service had 6.5 million paying customers back in October, but many people were understandably cautious. Were those numbers actually going to grow, or had Apple already scooped up most of the people who were interested? Apparently, the folks in Cupertino don't have much reason to worry. Financial Times sources understand that Apple Music recently racked up its 10 millionth paying subscriber -- not bad for a service that's barely half a year old. Spotify took 6 years to reach the same milestone, although it now has 20 million Premium subs and (thanks to its free tier) 75 million active listeners.