Retailers that get the most payback from loyalty programs are careful to measure vital metrics, like gross margin per customer and the lifetime value of a customer, which is tracked by using surveys and following forwarded emails to see who's recommending your store.
Here, CAC is cost of customer acquisition, MRR is monthly recurring revenue and software margin is the cash they keep for each customer after accounting for support and other costs.
Their plan was to sell low-margin baby goods with maximum customer service: Moms could place an order once and renew it on a regular basis, often with free overnight shipping.