"Every customer who buys an iPhone 4S at an Apple retail store will be offered free Personal Setup service, helping them customize their iPhone 4S by setting up email, showing them new apps from the App Store™ and more, so they’ll be up and running with their new iPhone before they leave the store."
They don't need to be new owners. Imagine a sale team that will sit down with millions of your users (existing or new), showing them what new apps are out there, reminding them to buy from your store and walking them through on purchasing your product again. This will sure generate a big spike overall.