New investors included Rick Braddock, former president and chief operating officer of Citicorp, and Donn Rappaport, co-founder and CEO of the American List Counsel.
The Series D funding will be used to expand the company's sales force and to continue to flesh out its features and serve infrastructure.
New York-based Linkstorm promises to boost advertisers' click-through rates by presenting a menu of links when someone rolls over an ad powered by its Banner Xpander technology. Brand clients include Cisco, E-Trade, American Express, and Wal-Mart, while agency partners include Ogilvy, Razorfish, Grey, Digitas, and MRM.
"Our message of restoring the ROI for display advertising is resonating with all players," said Linkstorm CEO Ari Brandt.
In January, Linkstorm named Brandt--former head of digital media for Condé Nast Business Media Group--as its new chief executive, replacing founder David Sidman in that role. Prior to Condé Nast, Brandt was director of ad solutions for the Yahoo Media Group, leading business operations for Yahoo Finance and Yahoo News and overseeing the launch of Yahoo Tech.
The company's existing investors include technology industry expert Esther Dyson and Jim Rutt, a principal at JPR Ventures and former CEO of Network Solutions.
Other clients include IBM, Microsoft, AOL, Meredith and The New York Times.