Jay-Z Meets With Twitter's Jack Dorsey, Raps About Him On New Song Out Tonight

Jay-Z and Twitter CEO Jack Dorsey hung out in the Hamptons today, TMZ reports -- just two famous billionaires going on a casual stroll with the boys. And tonight, Jay-Z is releasing a song in which he raps about his new friend Jack: "Black Twitter, what's that? When Jack gets paid, do you? For every…