Advertising groups issue dire slowdown warnings

Three of the world's largest ad groups have issued dire warnings about an industry slowdown, as economic upheaval throws planned spending on advertising from TV commercials to Web searches into doubt. The forecasts from Publicis, Interpublic Group and Aegis on Tuesday followed solid-third quarter results by each of the groups, showing they have so far weathered the storm. But with economic troubles deepening, the advertising market is now at risk of suffering its biggest slowdown since 2001.