lol yes the "quick reply box" is the one at the bottom julie, the short cut is there if for if you want to skip reading the rest of the thread and reply straight away in the proper way.
eg. if this thread was 4 pages long with explanations and i didnt want to read them all, i could just hold down Alt+Q to get to the reply page and once there instead of using the mouse to post it i could hold down Alt+S (its mainly for people without a mouse)
does that help at all? cos i think your rubbing off on me, im starting to confuse myself lol