Interesting idea: The Human Body as Touchscreen Replacement. The downside to using a touchscreen over something with physical controls is that you lose that instant feedback of where the buttons are. (Skip a song on an old-school iPod while driving? Easy. Do the same on a touchscreen? That’s trickier.) Your own location sense plus knowing exactly what part of your hand (or, in another prototype, ear) you’ve touched could really improve usability for applications that are suited for it.

BoingBoing explains why SMS messages are more likely to get through than phone calls or mobile data during a large emergency. (Short version: They’re async, so the phone or tower can retry later, and they’re momentary, so they don’t tie up a channel like a call would.)

The article doesn’t bring it up, but I’d add the magnifying effect of social media. If that SMS message happens to be a status update to Facebook or Twitter, you can tell a lot of people outside the area that you’re OK (or not) at once, even over congested airwaves or wires.

Update 2024: I wonder how well RCS fares under the same circumstances, and how well it falls back to SMS. Especially since it looks like fallback is an app feature, not a service feature, so I can imagine some third party apps forgetting or not bothering to implement fallback.

Also, the social media aspect no longer applies now that the networks have discontinued post-by-SMS.