App: Yo. User: Yo App: Yo User: Yo, sup? App: Yo User: Yo, you for real? App: Yo User: Yo, I’m out. A new app that lets you send “yo” to friends is real and its initial $1 million investment is also real. Merriam-Webster defines the word “yo” as an interjection used to grab someone’s attention. Yo certainly has done just that by grabbing everyone’s attention. Yo defines “yo” as “The simplest & most efficient communication tool in the world….