You might have noticed that the AP's Twitter account was hacked this afternoon and spread a report of a bombing at the White House. That yet another Twitter account was hacked isn't the interesting part, it's the immediate (if brief and shallow) plunge that the financial markets took. We don't really need any further reminders of the power of social media, but it's hard to ignore this particularly stark demonstration of the real-time effects. In this hyper-connected environment a breaking news tweet that was only live for a few minutes and, in retrospect, contained many glaring clues to its falsehood, caused the Dow Jones Industrial Average to drop to 14,567, from 14,697. Now, that only represents a roughly 1-percent drop, and it lasted only about as long as the tweet itself -- the markets quickly bounced back and stabilized. But it is a firm reminder that virtual events can have significant real world consequences.