• by Joe Mandese , July 26, 2007

Jason Heller, the founder and managing director of Horizon Media's interactive unit, is leaving the agency, to join The Laredo Group, a consulting company specializing in online advertising buying and selling, search marketing and optimization. Heller, who became Horizon's chief digital officer in 2005 when he and his partners sold Mass Transit Interactive to Horizon Media, leaves Horizon amid a senior management reorganization that is transforming the world's largest independent media services agency.

Carl Kotheimer, Horizon's executive vice president-marketing services, general manager and long Horizon President-CEO Bill Koenigsberg's No. 2, has also stepped down from a day-to-day role and is known by insiders to be transitioning out of the agency.

The changes come as Horizon has repopulated its senior management team with a team of executives steeped in brand strategy, communications planning and channel planning experience that are putting a new imprint on Horizon, once known primarily for its spot buying capabilities. That transformation has been orchestrated by Horizon founder Bill Koenigsberg who is seeking to make the agency competitive with the best and brightest of Madison Avenue's media and brand strategy teams.

It's been quite a transformation for Horizon, whose roots began as the barter media division of broadcast and publishing company Media General Inc., which Koenigsberg bought out in 1989 and re-launched as Horizon Media with the goal of building a big independent media buyer amid a consolidation and unbundling of media buying services at Madison Avenue's traditional agencies. Koenigsberg has fulfilled that vision. Horizon now claims billings of more than $1.4 billion, is being invited to pitch some of the biggest blue chip media accounts, has hired 75 new employees so far this year, and in June leased an additional 25,000 square feet at its headquarters on Third Avenue in New York.

Heller says his decision to leave two years after forming Horizon Interactive was due partly to the management changes at Horizon, but also because he wanted to try something different and wanted to spend more time on his underwater photography business. Heller, an avid scuba diver, is regarded as one of the photo industry's leading underwater cameraman, and is also known for his environmental initiatives to preserve underwater sea habitats. He will also continue to be a regular contributor to MediaPost's publications and events.

At the Laredo Group, Heller will serve as executive vice president, a new post, and will head the firm's newly opened New York office.