They provided a seemless entertainment through video at a time when TV cost too much, and movies were not all that great for the money. By over supplying a high demand they catapulted themselves into the checks and balances situation where they are now in. They beat both TV and movies and bittorrent to the fruit punch, the sweet spot so to speak. Instant on TV like entertainment that was both creative and more down to earth. Its like jackass streaming in real time almost. Its not pay per view but in the future if internet on demand takes off aka higher quality internet to compete with cable and microsoft, youtube will have to go the way of napster and netflix perhaps.