Some three years back, I made a presentation and suggested that it was not unreasonable to say that Engadget was nearly as influential as the Wall Street Journal in the impact they had on purchasing decisions. I was talking about buying of gadgets, but boy if today was an indication, it's true in the marketplace broadly. As techcrunch notes, when engadget published what turned out to be a bogus rumor that the iPhone and the OS had slipped, it knocked $4 billion from Apple's market cap -- that is influence. It's also a great lesson in how fast things spread -- Apple seemed to be on top of it pretty quickly, and still got hammered. This really makes me wonder if someone has figured out how to game the market using blogs to make a ton of money, what with the Yahoo rumor from a few weeks back that turned out not to be true and popped the stock in a huge way.