You can do a very, very similar thing for non-game SaaS services, too. (Hubspot calls theirs CHI -- Customer Happiness Index. It attempts to predict who is going to quit based on backtested statistical models. In practice, you can get almost sickeningly good results with heuristics that take ~3 lines to program. You can also then save those accounts by something as simple as "Have the sales team email them and talk" or, in my recent experience, "Send them an automated email reminding them that the software exists.")
As a user, those emails have sometimes had a negative effect for the company emailing me. Something they send me reminds me that the program exists, that I'm still paying a monthly fee for it, and that I really don't use it very much at all.
But in all fairness, I doubt anything they could have said or offered would have changed my mind at that point. It was just a matter of when I cancelled, not if.
I think your last sentence is important - you were already gone, it was just a matter of time.
If the numbers work such that losing 1% of customers means keeping 3% i.e. the email prompts them to leave/stay respectively, then it's worth sending.
Getting rid of low-value users - in this case those not playing - can have long term benefits of focusing the business on getting more custom instead of getting comfortable on revenue that may disappear at any point.
The reason for emailing you could also be to find out why you aren't using the app. Even if one ends up closing the account as a result, the information gained is valuable for improving the product.
Alternately, noting them but not sending them an email at all.
Much like a gym membership, the people who don't use it at all but feel like they should someday (as long as they're not nagged about not using it) are one of the most profitable subscriber segments. Sure, they'll leave eventually, but they're not using your service anyway, and until then it's free money.
Patrick, just to be clear: Are the heuristics you're advocating here just something along the lines of "E-mail this user if they haven't touched their account in X days" or is a more in-depth approach required?
