The full spec for SMS

The full spec for SMS (the protocol used to send short messages to cellphones) includes the capacity for a "Ping" message, which can be used to determine if a phone is on or off/out-of-range. This is the kind of standard network utility that is perfectly sensible in the Internet universe — chances are I can ping your computer right now and find out if it's on and where it's connected to on the Internet. Turns out that the idea of pinging phones freaks out a lot of people, though, as a German company discovered when they shipped a little Web app you could use to tell if your friends' phones were on or not, without alerting your friend or their carrier to the ping. The public outcry has caused them to abandon the project.LinkDiscuss