With NBC's ratings exceeding projections through the first half of the Games, the network has sold $25 million of ads since the start of the Beijing Games, said Senior Vice President of Sports and Olympics Sales and Marketing Seth Winter. In the past seven days alone, NBC has sold $15 million worth of spots. Before the Games began, NBC said that it had eclipsed $1 billion in ad sales from more than 100 companies.

Winter said NBC has seen particular interest from movies, packaged goods, insurance, automotive and pharmaceutical companies. The categories that have not advertised — express mail and casual dining — have been affected by the economy, Winter said. "It's been an amazing ride for us," he added.

NBC also released results from a Nielsen IAG study that found advertising during the Olympics produces better brand recall (+14%), message recall (+20%) and likability (+13%) than ads placed during regular prime-time programming. The results are even better for spots that carry Olympic themes: brand recall (+29%), message recall (+40%) and likability (+33%).

Bank of America, for example, saw its Olympic spots do better in brand recall (+30%), message recall (+26%) and likability (+33%) than its non-Olympics prime-time advertising, said NBC Universal President of Research Alan Wurtzel. McDonald's found that its IAG numbers increased as the Games went on, with brand recall jumping from +30% in the first two days to +53% on the 16th day. During the same time period, its message recall jumped from +22% to +40% and its likability jumped from +17% to +23%.

"These are pretty extraordinary findings," Wurtzel said.