Engadget apparently posted a blog yesterday claiming an inside source at Apple sent out an email notifying employees that the iPhone and OS X Leopard would see further delays. See if you can guess roughly what time the blog posting became widely known:

That’s one powerful and expensive blog post, as $4 Billion temporarily vanished into thin air (for about 5 -10 minutes) until it became known the message was false. While there’s some uncertainty over exactly what happened, either Apple itself issued an incorrect email (which engadget reported on after it was sent to them) and corrected it after, or someone was able to “fake” an email from Apple that engadget said was a “trusted source.”

Next thing you know there is a big argument going on all over the web, people are asking if bloggers should start adopting journalistic ethics, and a sampling of other bloggers are none to happy with engadget about this whole thing:

“What a joke. Engadget posts unsubstantiated rumor, AAPL drops. Engadget later posts correction, stock fails to fully bounce back. Reckless and irresponsible, Engadget. Thanks a lot.”

This person has a point – by 12:10 pm the stock only made it back to 11 am levels, rather than the more optimistic times Apple was experiencing around 11:30 am – and don’t even get me started on the good old days of 9 am or I might get teary eyed.

Now the Securities and Exchange Commission has declined comment on whether the spoof’s impact on the market would warrant an investigation – but let’s hope it doesn’t. Any Apple shareholder that sat on their butt and did nothing all day experienced a loss of a few cents per share, which may or may not have had anything to do with the little blogging mishap. The only people that lost anything were those that saw a blog post, and decided to instantaneously engage in a massive sell-off – otherwise known as hyper active daytraders. Just because they like to react to every bit of news or non news out there shouldn’t be anyone else’s concern.

What should be a cause for concern is if that’s how quickly a subset of people react to a bit of almost non-news, what the heck is going to happen when really bad, well sourced news comes down the pipeline for everyone to see? Like Asia’s richest person announcing China’s stock market must be a bubble? Or if Greenspan contradicts the current Federal Reserve Chairman and indicates the U.S. housing market just might keep getting worse and plunge the economy into a recession? Or when Bank of America’s CEO says things like:

“We are close to a time when we’ll look back and say we did some stupid things. We need a little more sanity in a period when everyone feels invincible and thinks this is different.”

In other words, what happens if today happens? Well all major markets go up of course. Investors collectively react to big news that would indicate stock prices might come under pressure soon by driving them up, and a few individuals investors react quickly to non news to drive stock prices down – a very interesting time in the stock market indeed.