Wow, even a thread that is just associated with a Feldbeard informational video gets nasty quick.
Because I know everyone cares a bunch about my opinion [sarcasm] I will say that I mostly agree with pablo. Anhyzer angle is different from OAT. But OAT is indeed its own concept, and I have seen one or two people throw with "intentional" OAT very well on a FH, although if you asked them about OAT they would probably tell you it is something to feed horses.
I think OAT is most easily defined as "wobble," which should remove most of the confusion regarding axes, etc. Think about the stupid human trick of someone keeping a bunch of plates spinning on a bunch of poles, the OAT is when the plates start to wobble when they are close to falling. I always heard it was caused by your arm moving faster than your wrist (or snap I guess), which kind of makes sense to me.
So OAT=wobble. Anhzyer angle does NOT equal OAT. Thoughts?