If you watch Top Gear (British car show) and happened to see the interview with Stephen Fry, you probably know that iPhone has an app for gay men who want to find other gay men nearby. There's an app that locates where child predators live in relation to where you (and your kids) happen to be.
There's also an app that helped a Texas homeowner know his house was being broken into, so that he could call 911. While he was on vacation in Connecticut.
I've got an app for that, too, for all that I don't have an iPhone, don't go on vacation often at all, and almost never that far away. Here's my app to prevent burglary:
21 minutes ago