App to tell you if your friend's smartphone on

Here comes an app that determines if your phone or your friend's smartphone is on with over 99 percent accuracy.

Billed as ON?, it also tells you if your phone is off.

Just send a text through the ON? app to your friend, and they will be able to text you back through ON? to tell you their power status.

If your friend's phone is off, the message "Is your phone on?" will be delivered the next time they open the app.

"You should not have to turn something off and then back on again to know that it is on. I want to know that my phone is on, reliably and safely, without all the fuss," Tavet Gillson, ON?'s lead creative director, was quoted as saying in the New York Times.

With the app, you can also find out which of your friends' phones are turned on and share the results with your social media friends.