"Yo" is the ridiculously simple app that everyone is downloading

There really is an app for everything -- even one that just sends out the simple two letter greeting, "Yo."

The free app, which is simply called "Yo," is available for iPhone and Android users.

"'Yo' is a single-tap zero character communication tool. Yo is everything and anything, it all depends on you, the recipient and the time of the Yo," according to the app store description.

Developed by San Francisco-based Life Before Us, LLC, the app's creators describe it as "the simplest & most efficient communication tool in the world."

And it is really as simple as it sounds.

Download it, choose the friends you want to send your "Yo" greeting to, and they get a push notification on their phone and that's it. Seriously.

"The 'Yo' itself is the message," "Yo"app creator Or Arbel, told CBS News. "'Yo' is a very generic word that can mean anything."

The app concept emerged when Arbel was asked by his boss at the time, Moshe Hogeg, head of the image-sharing app Mobli, to come up with a way to communicate with his assistant without calling or texting.

Then the idea hit Arbel while he was communicating with friends via WhatsApp. He noticed that "Yo" was a conversation between him and his friends -- so why not make things simple and create an app based on that concept, which requires no typing at all?

Thus the "Yo" app was born -- something Arbel calls "context-based" messaging.

"It's lightweight and you don't have to read the notification. You can choose to ignore it and there's nothing to open," Arbel said.

So far the app has raised $1 million from Hogeg's angel fund and has more than 150,000 users since launching in April, Arbel said.

And they can't stop talking about it:

For now, Arbel is focusing acquiring users but eventually hopes to approach companies to use this as a way to get their message across.

"It's very simple. It's a new way to communicate," he said.

So there you have it. As the app creators say, "It's that simple, yo."