« Let’s put that in perspective. If you were to sit and watch a billion hours of YouTube, it would take you over 100,000 years. 100,000 years ago, our ancestors were crafting stone tools and migrating out of Africa while mammoths and mastodons roamed the Earth. If you spent 100,000 years traveling at the speed of light, you could travel from one end of the Milky Way to the other… »

Source : Official YouTube Blog: You know what’s cool? A billion hours