Hanlon was not available for comment, and news of his departure came as a surprise to top Publicis executives. A VivaKi spokeswoman had no comment.

The news comes a day after Publicis finalized its acquisition of Razorfish, making it the largest digital advertising services organization in the world, surpassing WPP Group, according to the most recent data from RECMA, an independent research company that measures and ranks the billings, organizations, and other key metrics of advertising agencies. RECMA utilizes staff counts as the basis of ranking digital advertising organizations, and based on the addition of Razorfish, Publicis now has 9,468 people servicing digital advertising and media worldwide, vs. 7,703 for WPP.

A WPP spokesman challenged the ranking, noting that on the basis of revenues, WPP still is the biggest digital marketing services company in the world. Both WPP and Publicis claim to derive about 25% of their total revenues from digital media, though WPP combines digital and "direct," which presumably includes certain offline media such as direct mail, direct response television, etc.

Hanlon appears to be leaving Publicis on a high note, and a Publicis insider said he is "entrepreneurial" by nature, and may simply have grown bored as Publicis' digital organization has grown, and that he may be seeking a new challenge. In recent years, Publicis has added other executives to manage its ventures initiatives, some of which result in equity stakes in new media ventures, and some of which simply generate fees, or market intelligence and influence.

Before taking charge of the ventures group, Hanlon was part of the team that launched Publicis' elite media futures unit, Denuo, with its founder Rishad Tobaccowala. Before that he headed a number of digital media practices within Publicis' Starcom MediaVest Group, including its ground-breaking "TV 2.0 Practice," which centered around evolutionary TV advertising platforms, such as interactive, enhanced and addressable TV advertising initiatives, which is an area that is gaining new steam once again as the cable TV industry channels its efforts around Canoe Ventures, and as a wide variety of research, data, and technology companies race to adapt the selling and branding power of TV's sight, sound and motion to an age of micro-targeted interactive, one-demand media.

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