When Charlie Chaplin was nineteen years old he appeared in three music halls a night. On one fine day he started in the late afternoon at the half-empty Streatham Empire in London. Directly after the show he and his company were rushed by private bus to the Canterbury Music Hall and then on to the Tivoli. This constituted the maximum number of venues an entertainer could visit on an evening, and thus the inherent limit to a performer's productivity.

Yet, barely five years had passed before Chaplin would appear in thousands of venues across the world at the same time. His productivity had increased almost unimaginably. Most of this efficiency jump translated into lower prices, far lower than ticket prices for music hall. Chaplin himself, therefore, was able to capture only a small percentage of revenues. Yet this tiny cut made him the world's highest-paid performer.

Chaplin's experience epitomises the massive increase in productivity that modern service technologies have made possible. These efficiency gains often came as thieves in the night. They went largely unmeasured because inputs such as labour or capital have been used as output proxies. In addition, sharply falling prices kept expenditure shares modest, even as quantities skyrocketed.