hehehehehehehehe
Lets just stay on topic guys.
There seems to be only one solution to monetizing users that uninstalled your app and that is spamming their email box…
or by selling their email id’s/phone numbers to credit card companies 
caution: you can end up going jail.
There are definitely ways through app updates and notifications to get users back (ultimately who haven’t uninstalled) but this is correct, I wouldn’t dwell on it so much and look towards improving your app - these folks wouldn’t have monetized in your app anyway.
You don’t need to spam their email inbox, you can send emails that are likely to be well received.
For example if you have a game called “Candy Bird” and a bunch of email addresses to people who took the trouble to sign up inside Candy Bird it seems reasonable that they would be interested in your next game “Jumpy Bird”. Send them an email that begins with some information about who you are and how you got their email address and how they can unregister themselves from receiving more emails like this, then tell them about Jumpy Bird and give them the link to the Play page for that game. End the email with another link to the unregister page for good measure.
This will give your game an extra boost in its opening week for free.
By the time you’re ready to release your third game “Temple Bird” you will have even more email addresses. It could easily build up over time if you release a lot of apps.
If I remember well, you are not allowed to use people email address for unsollicited emails. Even if you include 10 links to unsubscribe from mailing list, these would still be unsollicited emails.
Unsolicited is the key word here - you are allowed to add newsletter sign ups to your app as long as it is opt-in. There are quite a few plugins out there that help you do it.
Ninja EDIT: as long as it is opt-in
The important thing from a ban/legal perspective is to read the rules of Google Play and any other app stores that you are using to distribute your app and then follow those rules. Also, you obviously need to follow the laws of the country where the app store is located.
My apps are integrated with appoptim new sdk for almost 3 weeks, so the new version is o.k. I thought about replacing their sdk, but I don’t know now, as I received my payment, 0.05$ for every download. I started to use their SDK as I thought it will not bug my users (it has a very small icon).
Be careful with sdk “outside the app” when you’re using PPD model.
