What started out as a ridiculous concept has turned into something extremely useful in Israel.
The country is engulfed in conflict, facing dozens of attacks each day by Gaza terrorists. Therefore, the Yo app has teamed up with the Red Alert: Israel app to alert citizens to the location of any rockets, mortars or missiles launched at Israel by Gaza terrorists.
The app's co-creators Ari Sprung and Kobi Snir created Red Alert: Israel as a "backup" warning system to Red Color, which is the emergency siren system that is supposed to warn residents 15 seconds before a rocket explosion.
Red Alert: Israel is its own standalone app, which you can get by clicking here for iOS and here for Android. However, Yo users can sign up for Red alerts and will get a "Yo" when there's an incoming attack.
It's great news when you consider that the app gained 950,000 users in just four days after Yo caught major media attention. It's also attracted more than $1 million in funding.