What if you traded Apple stock around Steve Jobs' January Macworld keynotes...would you make any money? Short answer is yes but buying Apple stock 10 years ago and holding would have been the better move. Also interesting is the market's reaction to OS X and Jobs' installment as CEO...Apple lost 7.3% of its market cap the day after the announcement.
David Pennock on the steep rise of Apple's stock after announcing the iPhone: "Jobs's speech could not possibly have revealed over $8 billion in previously undisclosed information".
Update: On the other hand, analysts think that Steve Jobs' mere presence at the company is worth $20 billion.