Will General Electric Company (NYSE: GE)'s NBC Universal experience the "thrill of victory" or the "agony of defeat" from the Summer Olympics in China? Odds are fairly good that the multimedia extravaganza may not be that thrilling to GE's bottom line.

Yesterday, the under-performing conglomerate announced that it had sold $1 billion in advertising for the games.

"We've always said that the Olympics is one of the most powerful properties in all of television," said Seth Winter, Senior Vice President Sales & Marketing NBC Sports & Olympics, said in a press release. "While we are thrilled with this milestone, we still expect to write more business as the Games begin and great stories continue to evolve."

Of course, such gushing is to be expected from an ad sales guy. But one thing that often gets forgotten when people write about television advertising is that commercial time is sold based on the network guaranteeing that a certain number of viewers will watch the show. If the audience does not materialize, the network has to give what's known as a make-good: usually free commercials on another show. The viewer numbers NBC has to hit are a closely guarded secret.