"Yo," I said to my colleague Kim Bhasin shortly after I joined The Huffington Post in 2014. His eyes widened along with his smile as he asked me, "Do you have the Yo app?" When asked why people should ...

Yo is a joke. It’s an app that does practically nothing, aside from sending a two-letter message to someone you know. There’s really nothing about the app that makes it unique—aside from the fact that ...

I spent a week on Yo, yo-ing to all the friends of mine who'd downloaded the app. Both of them. Here's how to use it: download, choose a user name, sign in, enter your phone number, wait for Yo to ...