Many attendees of the annual Cannes Lions International Festival of Creativity pride themselves on being forward thinking. But at this year's event, a lot of minds will be focused on one future date in particular: 27 July 2012, when the summer Olympic Games begin in London. If you want to know why this is, follow the money.

The Olympics are a prime cause of the industry's "quadrennial effect" – the lift given to global adspend every four years due to the happy convergence of major summer sporting events and the US presidential election. The precise impact of the world's largest sporting event remains a matter for debate, though Vincent Letang, ad forecaster at MagnaGlobal, has pegged the overall quadrennial effect as representing an extra +1.7% to US adspend growth in 2012. But there can be no argument that big events like the Olympics benefit the ad world, the odd ambush permitting.

So what's the extra cash going on? One largish chunk is accounted for by Visa – which has sponsored the Games since 1986, and has launched a new effort, entitled 'Go World', for 2012. Representatives of both client and agency (TBWA\Chiat\Day) discussed the campaign on stage during Visa's seminar at the Palais des Festivals earlier today. This year's activity is based around a series of TV ads, featuring famous Olympic stories of the past, narrated by the "voice of God" – actor Morgan Freeman. And the marketers also made room at the seminar for a genuine Olympic great who featured in one of these spots: Nadia Comaneci, the Romanian gymnastics legend who, at the age of 14, scored the first ever Olympic "perfect 10" at the 1976 Games.

To Patrick O'Neill, executive creative director at TBWA, Nadia's Olympic moment was an obvious choice for the campaign. "It takes 30 seconds and, it's like Clark Kent to Superman," he said. "It's when we saw perfection for the first time at the Olympic Games." More generally, when selecting a story to use in one of the ads, the creative team aimed straight for viewers' emotions, rather than their rationality. "We had a goosebump test," O'Neill added. "No goosebumps and we didn't use it."

For his part, Antonio Lucio, global chief marketing officer at Visa, offered a justification for the presumably steep costs the firm faces in sponsoring the Games, let alone hiring the voice of God for its ads, by pointing out that the Olympic-related activity lifts Visa's brand equity score by up to 30%. He was also quick to highlight the digital element of 'Go World', which aims to "harness the Olympic spirit into a social movement". Visa's digital campaign ecosystem encourages users to give individual athletes their "cheers", share athletes' stories via online videos, and submit their own videos of support. There have been around 9.2m "cheers" so far, with the three most engaged countries proving to be the US, Brazil and Russia.

The campaign's media strategy is very complex, this being the first Games since the multi-screening trend has really taken hold among consumers. Lucio pointed out 30% of US Olympic viewers will be "watching" this year's Games on three or more screens – TV, laptop, tablet, or smartphone.

And Nadia herself? Unflappable as ever, she adeptly demythologised her achievements – and gave us the real human story behind the iconic footage of her 14-year-old self used for the ad. Watching the scoreboard flash up its "1.00" – the Games organisers being forced to improvise, not having accounted for the fact that perfection might be possible – Nadia's thoughts turned to home. "I was too young to know what was going on – I was just hoping my mum and dad were watching me," she explained.

"I had no idea about history or anything."