A year from now, will chicken McNuggets be more popular than Big Macs? will every 20-something woman in New York buy leggings again this summer? Are trucker hats, which were so popular in 2003, poised for a comeback in 2009? The answers are worth billions of dollars to major corporations. When fast-food eaters start preferring chicken over beef, McDonald's needs to know months or even years ahead of time in order to place contracts with poultry farms, redesign menus and undertake expensive marketing campaigns.

Similarly, buyers for fashion outposts like H&M have to know a year or more in advance whether their customers will prefer leggings or skirts in summer 2009 because of the huge time lag involved in designing and manufacturing clothing. Automakers, device manufacturers and many other industries face similar problems.