Easy. Hypothetically someone puts out negative stories, the stock goes down, they buy a bunch of stock, and then the iPad comes out without problems (since they made the 'problems' up) and the stock you bought cheaply goes up!
I'm not saying that's what's happening here, but that's what the poster was talking about. It's certainly happened before in the stock market.
Alternatively, they could short the stock . You can read the link if you really care how it works, but the short version is that it's GOOD for you when a stock goes down. So if you're shorting a stock, telling bad stories about that company helps you.
All of this is illegal, by the way, so when people here say that this is what's happening, they're just guessing. There's no proof lying around on the internet, obviously.
Or, you can just play the ups and downs (particularly for a famously volatile stock like AAPL.)
I did this for a while on last year's drop back to sub 100. I'd buy when it dropped to the low 90's and sell when it hit 100. Did that about 5 times and luckily held on the last pass through 100. That's the risk... you never know when the thrashing will stop and a real upswing starts.