"When Cell Phones Fail":

This week's tragic collapse of the Interstate 35W Bridge in Minneapolis triggered another collapse of sorts: a jam-up of the cellular phone networks in the area. Bystanders and survivors tried to phone loved ones, only to find that they couldn't put the call through. So what's the solution? Two words: text messaging.

...Cell-phone networks are set up in such a way that text messages can piggyback on the streams of voice data traffic bouncing around the system. The digital messages, which amount to mere dozens or hundreds of bytes, can be slipped into the gaps in that stream.

"They're able to sneak through there, even when you and I are having a conversation," [Minneapolis Verizon spokeswoman Karen] Smith explained.

So if you don't know how to use the text-messaging feature on your phone, now is a good time to learn. "Get one of your nieces or nephews to teach you how to do it," Smith joked, "or stop by a Verizon store and ask them to show you."