The deal was financed by equity firm Bridge Investments and combines the search-engine marketing of Prime Visibility with the behavioral advertising expertise of AdOn.
Rosenberg will be CEO of the new company, which he said can help enhance online brands and traffic for the traditional media companies that the companies have "deep relationships" with.
The new company is looking at an online-advertising marketplace that could reach $50 billion in the next three years, with the Prime Visibility side helping to drive search-engine traffic and click-throughs -- Fox News Channel is already one of its clients -- and AdOn monetizing that by putting Web sites and media buyers together.
Seth Page, a specialist in mergers and acquisitions, will be chief operating officer and Richard O'Connor, who was vice president of finance and operations at Universal Domestic TV, will be chief financial officer.
AdOn president Steve Armstrong and Prime Visibility president Andrew Hazen will remain atop their respective companies.