Awesome.. I really had no idea then.
I use arachna frequently when i'm not trying to learn other players and i do this occasionally and never knew what it was called.
Though i thought they(the creeps) still attacked me.. will have to pay attention more.
It was used alot in DotA to help cancel out the swing back part of characters with bad animations, like Drow, but it also helps most characters because you're increasing the efficiency of your attacks anyway.