Having implemented its directive on personal data protection on Oct. 25, the 15-nation European Union (EU) is headed for a showdown with the U.S. The EU law appears to bar the widespread marketing of personal data that's so common in the U.S., a prohibition that presumably could reduce some kinds of transatlantic e-commerce. Among other provisions, the law strictly limits the transmission of such "sensitive" data as an individual's race, ethnic origin, politics, religion, trade-union membership, and sexuality. Some say in a worst-case scenario, the disagreement could block transatlantic data communications of multinational corporations, banks, and airlines.