Hmm, I could have misread it. Though when I see or hear rapid fire I usually think tapping and whatnot.
WoW tries to avoid frantic key tapping by having a global cooldown, usually 1.5 seconds. When you hit the key for one major command, it works, then you have to wait 1.5s before using another. (This is oversimplified, but go with it.)
In theory this should make for relaxed gameplay. In practice it can go very wrong.
If you wait 1.4 seconds before pressing the 2nd command, the system will say Haha, you hit it too soon, I'm going to ignore you!
If you wait 1.6 seconds the system should say OK, I'm ready, I'll do it. But you've introduced 0.1s of dead time where you've been sat doing nothing. You've cut down your performance by over 5%.
If you hit it at exactly 1.5s, you still can't win, because the Intraweb introduces latency, and the WoW servers have their own lag. So the result can be any of the above at random.
So what people often do is wait for what feels like the right time then hit the button. If it doesn't respond, they then start mashing the key rapidly until it does.
What I mentioned above is just an automated way of doing that. You press the button once, calmly. The action will happen as soon as it possibly can without any fuss on your part. It barely deserves the name macro, it isn't anything sophisticated, and it certainly isn't doing any decision making on your behalf. It's a simple workaround for the technical problems that online games inevitably suffer from.
In fact it's such a good workaround that Blizzard have implemented something along the same lines in the game itself. If you hit the key at 1.45s, they game is *supposed* to say OK, you hit it a bit early, but I will allow it. As soon as the 1.5s is up I will carry out your command.
But their system is far from foolproof. My keyboard mashing macro on the other hand, is rock solid. I stopped using it because Blizzard's improvements were 'good enough'. But I would set up the macros again in a heartbeat if I needed to.
