But, clearly, Apple created Ping to drive the sale of additional music — and I think that’s why Ping isn’t a standalone app — if it were, then clicking a “Buy”

But, clearly, Apple created Ping to drive the sale of additional music — and I think that’s why Ping isn’t a standalone app — if it were, then clicking a “Buy” link in Ping would take you from the (hypothetical) Ping app to the iTunes app. Then you’d have to remember to switch back to Ping to get back to where you were. I don't know how iPhone users live without a back button. edit: really folks?