A day after the recirculation online of an old newspaper story caused a temporary collapse in the price of United Airlines stock, Google and Tribune Co. offered sometimes conflicting versions of events while failing to pinpoint what started the bizarre occurrence. Tribune said the Google News search engine caused a spike in traffic by adding a Sept. 6, 2008, date to a 6-year-old story about United’s bankruptcy on the Web site of the South Florida Sun Sentinel. Tribune owns the Sun Sentinel and the Chicago Tribune.
