Yo app hacked to say things that aren't 'Yo'

“‘We can get any Yo user’s phone number (I actually texted the founder, and he called me back). We can spoof Yo’s from any users, and we can spam any user with as many Yo. We could also send any Yo user a push notification with any text we want (though we decided not to do that).’

[…]

on Vine, Yo was seen playing bursts of Rick Astley’s Never Gonna Give You Up.”