The second measure to use in assessing whether or not you’ve achieved must-have status is your product’s retention rate, which is simply the number of people who continue to use your product over a given time.

Kate showed the company that the number of renewing customers was a far more important metric for success (and far cheaper) than the number of new customers acquired. Magazines.com also changed its home-page messaging in order to speak to existing customers, added more renewal offers, and improved customer support for paid users.