Minecraft Herobrine Myth: Where Did it Start? Was it Real? Did Notch Play a Joke on All of Us?

Hi, I've been reading about Herobrine and the commotion it stirred up around the internet. But, where did this myth about Herobrine even start? I've heard that Notch created it to scare people and cause a commotion, but many people said it was fake and someone made it up. But, in the 1.6.6 update, Notch 'removed Herobrine' from what I see on Minecraftforums and Wiki. So, was Herobrine a real, but rare part of the game just to start up myths and scare people? Or was he never real and Notch said he removed Herobrine as a joke? What do you think?