Until recently, Len Ellis was executive vice president at Wunderman, where he charted the course in data-based and technology-enabled marketing communications, including the firm's strategic alliances and worldwide interactive strategy. Earlier, he was managing director, interactive integration at Y&R 2.1, a Young & Rubicam start-up consulting unit. He joined Y&R Group as managing director, interactive services at Burson-Marsteller. Len led interactive services at Messner Vetere Berger McNamee Schmetterer EuroRSCG, and started and led the information industry practice at Fleishman-Hillard. Len's book of essays on marketing, based in part on this column, is "Marketing in the In-Between: A Post-Modern Turn on Madison Avenue." He received his Ph.D. from Columbia and reads informational and mathematical theory for fun.