If you take all the streaming music services and put them all together, they would still add up to a tiny fraction of the size of YouTube. YouTube is by far the biggest source of music online. How big? Let me give you some stats. (1) The best estimates say there are 1.1 billion videos available on YouTube. A lot of those are cat videos, of course, but a sizeable number have to do with music. (2) If you add up all the views of all the videos, you get a number somewhere around 7.8 trillion. Yes, trillion. But get this. (3) Just over 5% of all those 1.1 billion videos have 10,000 views or more. Doing the math, that means these videos have generated 7.4 trillion views. In other words, there are about a billion videos that almost no one has seen. More next time.