Is this a parody? If I sign up for your app to check it out and decide I don't like it, I'm going to get emails about it every 4-7 days until the end of time? If I buy something from you once, emails every month unless I decide to buy something again? If every app and online store I've ever used took up this tactic, my inbox would be an absolute nightmare. It sounds like a great way to generate unsubscribes and spam reports.
Basic info is basic. (I've done this for 10 years at least)
And yes, it works - Not everybody uses email the same way, nor everyone thinks is offensive to get messages. Yes, people unsubscribe at every email sent, and still, the majority of folks don't need to have a clean inbox and can live their lives just fine with emails from their retailers.
