What is this? Whenever possible, ask your users to register as a member and sign up for your newsletters.

Why should you do this?  There is an old saying: “The Money is in the list”.  It means you need to have a mean to constantly communicate

Who else is doing it? Every app that requires a login or registration such as Facebook, Twitter, Groupon, Living Social, you name it.  Most developers are getting onto this trend.  And Apple is adding new submission guidelines to curb this registration mechanism.  Apple wants to keep the customer list to itself.  They want to get a cut on every transaction.

How can you do this? The workaround for Apple’s submission guideline is to require the user to login before using your app.  You can provide some kind of software as a service in your backend and make it an essential part of your app.  During the registration process, add a little checkbox to encourage your user to sign up for your newsletter.