Found this on the US forums - I had to post it here. :)
What is a Boomkin? Is it similar to a Moonkin? Does for the form even exist? I mean, I saw this funny WoW video with a "Boomkin" in it, but that was all. What's a Boomkin?
Its a more evolved form of a Moonkin. A Moonkin goes through different stages in its life.
Noobkin: This is the first form of Moonkin. Its new to the spec and generally doesn't know much. Its life in this stage can be short as most don't live past it. Moonfire is the preferred spell.
Oomkin: In this form the Moonkin is still new but knows little of actual mana management and gearing and thus don't last long in battle. Moonfire is the preferred spell.
Moonkin: This is the adult stage. It is able to use its abilities to its fullest potential.
After Moonkin it can advance to a new stage in life. Where it chooses a specialty in what it does. The choices are as fallowed.
Boomkin: These guys are psycho!!!! They enjoy big crits and big explosive damage. Very unpredictable in battle they prefer starfire as it shows the highest crits possible to a Moonkin.
Panzerkin: These guys focus on armor and stamina. Charging through enemy legions as they blast things to oblivion they are near invincible. The do however have little offensive ability. Moonfire as favored spell.
Doomkin: Deadly and precise. They can do more damage then any other Moonkin type. Preferring steady and predictable yet high blasting abilities they are deadly to all enemies. Preferred spell is wrath.
After this stage there is still one more. Infinitely stronger than the other forms they are incredibly strong. Legendary in power.
Space Chicken!!!!!!: These are a deadly combo of all the previous forms. Well balanced in all manners they can be nearly unstoppable. It is only legend however as very few have been known to exist. Moonkin are like an iron cannon as a mage is like a glass cannon. An iron cannon can take a sword to its side easily but when hit by fire from the glass cannon it will melt.