Under terms of the sale, Chinadotcom acquired 2.5 million shares of 24/7 Media, making it the company's largest stockholder. Chinadotcom's CEO Peter Yip will join 24/7 Media's board of directors. In exchange, 24/7 Media acquired a 20 percent stake in Chinadotcom's 24/7 Media Asia unit.

In early trading today, shares of 24/7 Media were trading down 5 percent at $12.12. Chinadotcom's price also dipped a shade, trading this morning just over $16.00, down 75 cents from the opening.

Paul Warburg, VP of investor relations at 24/7 Media, touted the agreement as essential for the growth of his company. "It's the largest marketplace in the world and it's just beginning to accelerate it's growth and we wanted to be a more active part in that," he said.

As part of the pact, 24/7 Media will also provide technology-based marketing tools to 24/7 Media Asia, the Pan-Asian spin-off of Chinadotcom. Previously, the company offered only banner tools in the Asian market.

The tools will provide the company with opportunities to generate additional revenue and boost its capability to help Web sites generate income from their inventory, a company statement said.