Move over Travelocity, Expedia and Orbitz. A new generation of travel Web sites is emerging, and they're looking to revolutionize the online purchase of airfares. The brainchildren of PhD-in-mathematics types, the sites use what is called predictive technology.' No crystal balls are involved: The sites mine and analyze historical airfare prices so consumers will know better when to push the button and buy.Hello, Good Buys: Four Sites That Offer Fare Help (Washington Post Sunday Travel)
The four sites?