I have tried it but the biggest fail with it is to communicate with other people all you can do it see what the bought follow or be followed but no real way to talk with that person like .. How is that album or song before I buy it etc .. So end result is yes I have one but don't really go on or use it
"Ping" (Apple's) is a social network similar to twitter where you can follow artists friends etc as opposed to the original which operates by sending an ICMP echo request to a target host and then waiting for a response.