Local media have already reported on the rash of smartphone thefts on public transportation and on city streets. But how, exactly, do these creeps go about swiping your iPhone or Nexus? Simple: group strong-arm robbery. According to a recent report by CBS 5's Joe Vazquez, a smartphone grab typically goes like this: hooligans see somebody with their head in their phone, they work together by calling each other on their own cell phones to let them know a potential victim is coming their way, then they "swoop in, grab it, and off they're going."

These muggings, it seems, are also becoming increasingly violent. So, you know, do be careful, especially if you're listening to music and checking your email while riding the bus or walking down the street.

"If you really need to text and its nighttime, go into a coffee shop or do something so you're not walking down the street and become victimized," SFPD Captain Terry Barrett explained.

Update: Stephen Woods has a helpful post on how to automatically erase data from your iPhone in case it's stolen.