Herobrine(Pronunciation) is the subject of a community-made "creepy-pasta" (Creepy story). He is one of the major community icons of Minecraft.
Herobrine has not been present in any version of Minecraft.
"Canon" of Herobrine is widely regarded as the first image/story ever posted about Herobrine, as well as the Brocast stream. Anything posted after these two events are considered as fanmade