Other OS’: don’t let those non iOS users go to waste. Yardsale’s take on keeping prospective users in the pipe. 

User retention: @Etsy is trying to keep you around with Every Time You Go Away by Paul Young when unsubscribing from their email newsletter.

User retention: when you log out of Twitter (@twitter), you are reminded that you can surf the site from your mobile browser on m.twitter.com or use one of the various mobile apps.

User retention: This happens when you unsubscribe from Appsumo. At least they’re handling it with some humor. 

Kickstarter (@kickstarter) uses a user retention call to action for those that are not yet convinced to chip in. They promise to inform you shortly before the pledging ends. After a successful funding it turns into a button and says: “Don’t want to forget? Click the star to add this project to your profile.”

User retention. If you cancel an Audible (@audible_com) account because it does not work with your device, Audible offers Amazon vouchers to buy a new device (if you actually continue to stay on the service):

Audible will give you an Amazon promotional claim code good for £50 off the purchase of select electronic devices when you join the AudibleListener® plan for 12 months at £7.99 per month. If the product you choose is less than £50, you will receive the device for free (clarification: the promotion has been taken down at the time of writing).