The document discusses 5 key customer metrics that every manager should know: 1) Net Promoter Score, which measures customer recommendations; 2) Customer Profitability, which measures how much profit each customer generates; 3) Customer Retention, which measures loyalty and retention of existing customers; 4) Conversion Rate, which measures acquiring new customers from prospects; and 5) Relative Market Share, which measures a company's share compared to competitors. The document was created by Bernard Marr to help companies better understand and leverage customer data.