A lot of rubbish in this thread.
Stick shaker activation is a PRE-stall warning for such aircraft which have indistinct naturally occurring pre-stall buffet and stick shakers are installed on such aircraft to alert the pilots that a stall is imminent and not to indicate that a stall has already happened.
So at stick shaker activation the aircraft is fully controllable and not stalled.
In my previous pre-airline life I flew for two transport squadrons, one flying Hercs and the other the B707.
Stalling and the recovery was part of the training on both types and on the B707 stalling the aircraft, both clean and fully configured was part of the post heavy maintenance flight check schedule.
The fully developed clean stall and recovery maneuver in the B707 was a relatively mild experience and certainly nowhere near violent enough to cause injuries as suffered on the QANTAS aircraft.
Now before anyone leaps down my neck, I am fully aware that a B707 is not a B747 but I have flown many thousands of hours on both aircraft types and although I haven't had the pleasure of stalling a B747 aircraft I have done the stall and recovery exercise in the B747 flight simulator and it is most definitely not a boneshaker. The simulator remained firmly attached to it's mounting bolts! I have no reason to suspect that the stall characteristics of the B747 would be any different to that of the B707.
My opinion is that the QANTAS B747 had a wake turbulence encounter with a higher heavier aircraft in the same holding pattern.
There was a recent A380 wake turbulence incident where a Challenger aircraft was affected and lost control and and after recovery was eventually written off so wake turbulence encounters can be violent and should be avoided at all costs.
Cheers,
BH.