The market leader in 1991 was the oldest of the four firms, the solid and serious CompuServe, owned by H&R Block. Its subscribers, numbering roughly 600,000, were largely male, a mix of computer hobbyists and some businessmen. CompuServe took the way of substance over style, betting that pure data was what mattered to its customers, who seemed to appreciate the no-nonsense, text-only interface. Since it originally used idle time on commercial mainframes, CompuServe gave its users numerical identifications (example: “70014,2316”), and sold them on utility: “When you join CompuServe,” its ads promised, “your computer becomes a time-saving, money-making, life-enhancing tool.”

Tim Wu, The Attention Merchants, loc. 698