Clever trick from Jason Snell:

I realized, then, that the best way to discover if the power was just out to my house or if it was the whole neigborhood was to open the Settings app on my iPhone and tap on Wi-Fi.

Everyone’s got a wi-fi base station. On a normal day I can see a half-dozen SSIDs around my house and yard. But on this sunny, calm Tuesday morning: Nothing. Not a single signal. (Not even a battery-operated device offering wi-fi for tethering purposes, that I could see.)

So it wasn’t just me. The entire neighborhood was out. The wi-fi signals (or lack of same) were what told the tale.