If a customer hasn't interacted with the system for a certain period of time, you can have a We Miss You Offer go out to them.

An interaction is counted when they sign up for a new offer, redeem an offer, fill out a review form or submit a text message through the communications system.

Each time they interact with the system in one of those ways, their "interaction timer", if you will, is reset. So, as long as they continue to interact, they won't get these offers.