The report, which was pulled from the iReport site at about 10:15 a.m., was dramatic: "Steve Jobs was rushed to the ER just a few hours ago after suffering a major heart attack. I have an insider who tells me that paramedics were called after Steve claimed to be suffering from severe chest pains and shortness of breath. My source has opted to remain anonymous, but he is quite reliable."

At 9:41 a.m., about the time the report was apparently posted, Apple stock was trading at its high for the day at $106.50 per share. In just 11 minutes, the share price fell more than 10 percent, to $95.406.

Thanks to Apple's quick and firm denial, the stock recovered early losses, but at midafternoon was still trading below $100.

The Credibility of Rumors

Shortly after removing the story, CNN issued a brief statement that read in part: "After the content in question was uploaded to iReport.com, the community brought it to our attention. Based on our Terms of Use that govern user behavior on iReport.com, the fraudulent content was removed from the site and the user's account was disabled."

There was no word about whether the report was a deliberate attempt to manipulate Apple's stock price, although it's likely that possibility will be investigated carefully.

As any grifter knows, the best cons play into people's preconceptions. For much of the past year, online medical evaluations of Jobs have been a cottage industry. Things reached a fevered pitch in June, when he appeared at Apple's Worldwide Developers Conference looking thin and wan.