• by David Goetzl  @dgoetzl, July 25, 2012

Some Olympic moments are never forgotten. The winners? Hardly.

Mary Decker’s fall in 1984. Kerri Strug’s vault on a bum ankle in 1996. Michael Phelps going nuts when a teammate saved his quest for eight golds in Beijing.

But name the winner of the Decker race, another person on Strug’s winning team or the Phelps savior?

The argument that athlete narratives and profiles drive more interest in the Olympics than the events themselves will be put to the test in the London Games. NBC is counting on this trend to drive interest in its prime-time coverage like never before.

Unlike in Beijing four years ago, there will be no events shown live. Media fragmentation continues to escalate with alternatives such as Netflix and Hulu that could grab viewers away. And, NBCUniversal is streaming all Olympic events live online with some fancy enhancements hours before Bob Costas signs on with the evening coverage.

With swimming and gymnastics live in prime time, ratings for the Beijing Games topped the 2004 Athens event by 8% in household numbers. Based on one estimate, NBCU isn’t so sure London will bring an increase.

An estimate given to one London advertiser – President Obama’s campaign – calls for a 15.3 average household rating in prime time. That would be a 5.6% drop from Beijing.

Still, by one metric, that would top the Athens Games by 2%.       

The 15.3 estimate given to the Obama campaign, according to an NBCU political file, could be different than what NBCU is giving to other advertisers. Multiple factors could affect estimates given to a particular advertiser. The Obama campaign plans to run 15 prime-time spots.

(The Obama spots will run on 15 of 17 Olympic nights, including the first 12, according to that NBCU file. MediaPost had reported it would be the first 15 with no interruption.)

Still, even if 15.3 is the estimated household rating being widely floated to advertisers, it wouldn’t be a surprise if NBCU is taking a conservative approach to avoid paying out make-goods. The NBCU file indicates, however, that the campaign's buy comes with no guarantee.

A 15.3 rating would equate to 17.5 million homes. On weekend afternoons, where the Obama campaign has bought spots on consecutive Saturdays, NBCU has provided an estimate of a 7.0 household average (8 million homes).

On weekdays, where the Obama campaign may be looking to appeal to female viewers, an estimates calls for a 4.9 household average (5.6 million homes). Both the weekday and weekend time periods could have people at work or on the go turning to NBCOlympics.com rather than the TV.

If NBCU’s ad sales group is being slightly conservative, the company’s research chief Alan Wurtzel is bullish. In June, he said he believes the Olympics will rank as one of the top-five most-watched events in TV history.

Of course, NBCU can't control which compelling stories unfold to drive ratings. Will a national debate break out whether a U.S. sprinter should replace a teammate on a relay team to have a shot at a record? Will the South African runner with two prosthetic legs pull off a stunner and make the finals?

“It’s really going to be the storylines behind the athletes and what’s going on there,” said GroupM researcher Lyle Schwartz.

Even if people see magic live online at work, there’s reason to believe they’ll tune in for analysis, debate, interviews and touching pieces about the competitors later. The no-frills online coverage of an event could create hunger for more.

“I think it’s only going to add to the interest of wanting to see it again in prime time as part of an overall show,” said Lee Berke, who advises sports networks.

That’s where NBC does have some control to create drama.