It's hard to believe, but it's been five years since YouTube launched and changed the way people share video online (it was acquired by Google a year and a half later). To celebrate its birthday, YouTube has just announced a major new milestone: it's streaming a whopping two billion views per day (the company notes that this is "nearly double the prime-time audience of all three major US television networks combined"). To help commemorate the occasion, YouTube is also launching a new channel of videos called "My YouTube Story", which includes a collection of clips featuring people around the world talking about how YouTube has changed their lives.