This is a tip that I learned last year during the hurricanes (Katrina and Rita). In most cases this was the only way to contact family members in Louisiana. I think with hurricane season in full force (no pun intended) this is a good thing to know. When a land line is unavailable and all you have is a cell phone even that is useless sometimes. During storms (or in "dead zones" while traveling) when you don't have a signal and a call won't go through, try a text message.
This is a great tip and she's right... it took about a week or so before we could even text over here in Mississippi after Katrina, but it works more times than not when you can't get a cell call to go through. I'll never forget almost a week into the aftermath with no communication, gasoline a precious commodity and no electricity, we took a risk and set out to Florida hoping we would make it and find some gas on the way so we could stock up on more food and supplies and hopefully a hotel room for a hot shower. As we crossed over a high rise bridge in southeast Mississippi, I realized there were a lot of cars pulled over there and found it odd until I realized that people were pulled over because they were picking up a cell phone signal!