Call British Airways from London after 11 o'clock at night to book a flight, and you will be answered in an American accent. “You sound as if you are in New York,” you say. “That's because I am in New York,” comes the reply. British Airways is one of a growing number of companies that use technology to turn time zones to advantage. No need to keep operators up half the night in Britain when the rotation of the earth provides a wide-awake American alternative.
 　  The benefits are familiar. The financial markets, which pioneered the three-time-zone world, have grown used to operating 24 hours around the globe. Other businesses are heading in the same direction. One pressure for them to do so is productivity. Put together a business deal or a research project with three teams working in shifts, and you save days. Another is technology. As more and more services can be assembled far from the customer and sold down a telephone line, it becomes easier to produce them where skilled staff come cheap. Lots of the paperwork for things like insurance claims and credit-card records can be done in developing countries, where there are more educated workers than jobs for them.
　　The problems are familiar, too : Any old-fangled manufacturer with a continuous process knows that shift work needs careful management. The evening shift may leave a mess behind for the night shift to sort out, and the night shift may bequeath a worse mess for the day shift. Worse, while the night shift in the average coal mine or paper plant lives just down the road from the day shift, the Tokyo bond-dealing team may never meet the chaps in New York, and analysts in Singapore may know their counterparts in London only through telephone conversations squeezed between the end of one day and the start of another. At the least, companies need to ensure that international teams know what is expected of them, and find substitutes for the congeniality of teams of the old-fashioned unvirtual variety.
　　Customers, too, can be an obstacle to global shiftworking. People who live in different time zones are likely to laugh at different jokes and take offense at different phrases. Some large banks have found that customers prefer to push buttons and hear a recorded voice rather than talk to a human being in a faraway country.