Starbucks became the market leader in an American coffee-shop explosion, and now has 1,500 sites across the States. It benefited from what the social commentator Faith Popcorn has identified as the search for a "third place", somewhere that isn't home or work, where people can meet and relax. With their tasteful furnishings, calming music and free newspapers, the new places were less threatening than alcohol bars, cheaper than restaurants, and the ideal environment in which to find a life partner. The phenomenon was validated when coffee bars provided settings for two of the great modern situation comedies, Frasier — which features the fictional Cafe Nervosa in Seattle — and Friends. Both are leisure-time porn, providing busy viewers with a tantalising glimpse of a world in which witty, attractive people spend all their time hanging out and drinking coffee.

Call it time porn. Just as sexual pornography titillates us with images from a forbidden world in which casual sex is there for the taking, do modern images, on television shows and in advertising, show us free time, a thing we covet but cannot have?

The characters of "Seinfeld" wallow obscenely in unscheduled time, as did the characters on "Cheers," probably the mother of all time-porn shows.