Yo, the pointless app that lets you message the word "Yo" to your contacts (and nothing else) has been hacked by a college student and his two roommates. The trio has been able to acquire any Yo user's phone number and spam them with multiple messages, though they opted not to abuse the latter discovery. Yo has confirmed the hack and promised a fix.
Meanwhile, a Vine video has appeared showing the app playing Rick Astley's "Never Gonna Give You Up" instead of its typical notification sound, and a post on Instagram supposedly shows an unauthorized message being pushed through the service.
So it turns out an app that was built in eight hours and has access to personal information can be hacked. At least it's free.