Business Insider
Yo, the app with the single purpose of sending your friends a "Yo!" notification, was originally conceived of as a streamlined buzzer of sorts.
Yo was created by developer Or Arbel, but the idea behind the app first came from Israeli investor and Mobli CEO Moshe Hogeg.
$4, Hogeg detailed the app's conception.
"I like to do things in the easiest way," Hogeg said. "We are always looking for the easiest way. My secretary, I love her, but I hate to tell her to come."
After Arbel turned Hogeg's idea into a working product, Hogeg said that he even uses the app to stay in contact with his wife. "My wife, she complains I don't call her enough during the day. Now I can send a push notification anytime I want."
Yo's success has spread like wildfire. The app has already broken into the Top 5 in Apple's App Store, but Yo's continued longevity is still up for debate, $4
You can read our own interview with Yo creator Or Arbel $4