The web homepage for Yo.
The Web home page for Yo.

Yo. We only just heard about you and already you’re super-popular. And getting hacked.

Yo is a simple app with little apparent first-glance reason for existing. Install it on your smartphone. Create an account. Connect with friends. Then send them this message: “Yo.” Over and over again. That’s all there is to it.


The Yo buzz comes from stories earlier this week that disclosed the creators of this oddball app, with 50,000 users as of a few days ago, had raised $1 million in angel funding for their project. Here’s Yo’s Creation Myth, as recounted in the Financial Times:

As is fashionable these days, Yo began as a somewhat accidental side-project of another start-up. Yo’s co-founder and chief executive Or Arbel was asked by Moshe Hogeg, chief of image-sharing app Mobli, to make an app with one big button that could call his assistant without having to pick up the phone or compose a text message. Mr Arbel, a former iOS engineer at Mobli, was working on a stealth financial start-up, Stox, and said he didn’t have time. But sometime later, he remembered the single-character text conversations he had over WhatsApp with a friend: ? instead of “how are you doing?” and ! to reply “great”, or simply go back and forth saying “yo”. “We communicated without saying anything,” Mr Arbel said.

Eight hours of coding later, he had combined the two into Yo, and shared it with his Stox colleagues. “They all loved the simplicity,” Mr Arbel says, “except one who said this is the stupidest app he’d ever seen.”

Let’s say the jury is still out on how stupid Yo is or whether, as some have been quick to say, Yo is a sign of the apocalypse that will end Tech Bubble 2.0. You don’t have to think too far back to recall a time when people were scratching their heads over what possible use Twitter might be. It’s not hard to imagine smart developers turning the Yo platform into a customized personal alert system — someone out there is already experimenting with Yo as a World Cup goal announcement service — and winning a big following.

What we do know is that getting a little media exposure has triggered a mini-Yo-mania, with the app getting a huge surge in downloads and traffic. Before appearing in the media earlier this week, Yo had reported about 4 million messages sent in the 10 weeks since it launched on April Fools’ Day. The company said it handled 3.7 million messages on Thursday alone.

The media spotlight on Yo also has attracted hackers, who with lightning speed uncovered a series of big and small security issues. TechCrunch was first with the story earlier Friday, reporting on the exploits of a Georgia Tech student:

The student emailed TechCrunch detailing what he alleges are the results of the hack: “We can get any Yo user’s phone number (I actually texted the founder, and he called me back.) We can spoof Yos from any users, and we can spam any user with as many Yos as we want. We could also send any Yo user a push notification with any text we want (though we decided not to do that.)”

Yo’s creator, Or Arbel, confirmed both the Georgia Tech hack and other security breaches. The company said via Twitter, “We are working on the securities issues that came to our attention. We want you to know we take this very seriously.”

Yo: Publicized, Popular and Now Hacked 20 June,2014Dan Brekke


Dan Brekke

Dan Brekke is a blogger, reporter and editor for KQED News, responsible for online breaking news coverage of topics ranging from California water issues to the Bay Area’s transportation challenges. In a newsroom career that began in Chicago in 1972, Dan has worked as a city and foreign/national editor for The San Francisco Examiner, editor at Wired News, deputy editor at Wired magazine, managing editor at TechTV as well as for several Web startups.

Since joining KQED in 2007, Dan has reported, edited and produced both radio and online features and breaking news pieces. He has shared in two Society of Professional Journalists Norcal Excellence in Journalism awards — for his 2012 reporting on a KQED Science series on water and power in California, and in 2014, for KQED’s comprehensive reporting on the south Napa earthquake.

In addition to his 44 years of on-the-job education, Dan is a lifelong student of history and is still pursuing an undergraduate degree.

Email Dan at:


Sponsored by

Become a KQED sponsor