Last month an unlikely underdog stunned the marketing world at the International Cannes Advertising Festival. At the show, a single marketing campaign took home a Grand Prix award in three categories simultaneously--direct, cyber and PR-- something that had never happened before in the 50+ year history of the show. Contrary to what you might expect, the unanimous winner of this unprecedented victory was not a Fortune50 brand with an advertising budget of millions, but a small Tourism board promoting a little known island off the Great Barrier Reef.

The winning campaign was called the "Best Job in the World" and was essentially a big online job search conducted through social media for a new "caretaker" for Hamilton Island in Queensland, Australia. Done on a comparatively paltry marketing budget of just $1.7 million dollars and reliant on fortuitous PR and word of mouth, the campaign achieved stunning results, including over 34,000 video entries from applicants in 200 countries, and more than 7 million visitors to the site who generated nearly 500,000 votes.

Just two weeks ago on July 1, the winner of the competition--a 34-year-old British man named Ben Southall started blogging and touring around Queensland, finally bringing the competition to a close. For the next six months, he will be touring around Queensland, sharing his adventures through a video blog, writing, Twitter account and Flickr photos-- generating even more interest in Hamilton Island and all of Queensland in the process. The tangible results for the island are rolling in as well: Amway Australia chose it as the site of their upcoming annual conference, and domestic Aussie airline Virgin Blue just started flying a direct flight between Sydney and Hamilton Island, due to the rise in demand from travelers wanting to get to the island.

I realize that tourism and the travel industry may seem far removed from your business. Unfortunately, we don't all have the natural beauty of Hamilton Island to fall back on when starting our marketing campaigns. Still, a big part of the reason for the amazing success of this campaign was not what they were marketing, but how they used social media to do it. In that, there are some lessons anyone trying to promote a product or service could use:

1. Make it believable. Many marketing groups would never make a claim if they can't provide substantial evidence. How might Tourism Queensland prove that their job is the best in the world? They can't. But it is believable because it is a beautiful place and fits what many people's definition of a dream job might be.
2. It's not about how much you spend. One of the major benefits of smart public relations and social media is that it scales in a way that advertising typically doesn't. In other words, you don't have to pay more to get more. The real trick is to have something worthwhile to say that people can't help talking about. You need a good story.
3. Focus on content, not traffic. The typical marketing campaign focuses on traffic to some kind of site. For Tourism Queensland, the biggest payoff of this campaign was having over 34,000 videos on YouTube from people around the world talking about how much they love Queensland. Aggregate the views of all those videos, and multiply them over the long term and you'll start to understand the true impact of their campaign.
4. Create an inherent reason for people to share. Another element of this campaign that worked extremely well was the fact that there was voting enabled on the videos. What this meant was that after someone submitted their video, they had an incentive to share it with everyone in their social network online to try and get more votes.
5. Don't underestimate the power of content creators Most recent statistics point to some number between 1% and 10% of the user base of any social network are the active content creators. Though these percentages may seem small, the potential impact of some of these individuals are vast online. It could easily become the secret weapon for your next marketing campaign.
6. Give your promotion a shelf life. The best thing about this campaign may just be the content yet to come. Ben, the winner, just started blogging and sharing videos and photos, but the content is already engaging, high quality and inspires you to dream of making it to Queensland yourself. Over the next six months, his itinerary will take him across the state of Queensland and unlock many other unique opportunities. Best of all, this content will live on far beyond the time span of the campaign.

Read more of Rohit Bhargava's Influential Marketing blog on Fast Company.

Rohit Bhargava is SVP of Digital Strategy at Ogilvy PR and author of the award-winning book Personality Not Included, a guide for brands to be more authentic. He writes the popular non-obvious marketing blog Influential Marketing and speaks frequently around the world on social media, marketing and the power of personality. Follow him on Twitter at @rohitbhargava or become a fan on Facebook before July 31 to be among the first to get a free download of his new ebook on August 1.