Searching For The New Heart Of Madison Avenue, Interpublic Thinks It's Closer To Wall Street

Interpublic finally went public with its new digital media trading system, officially joining an expanding field of big agency holding companies that are trying to become Madison Avenue's equivalent of Wall Street's investment banking firms. Interpublic said the new system, dubbed Cadreon, initially will make a marketplace around online display, online video and mobile media buys, but would...