In the WWDC keynote, right around 1:18:30, Scott Forstall’s nervous typo started a slide which ended up knocking about $5 billion dollars off of Apple’s market cap.

To be fair, it wasn’t just the typo, though I felt it in my gut the instant that happened. The stock’s drop from the mid-124s down to nearly 120 almost exactly matches the duration of the iPhone web apps section of the keynote. Rumors and expectations can be expensive.