Tropical island. Eleven competitors. Osama bin Laden. Porn scandal. Prize? Best job in the world.

This is not a reality TV show, but a contest playing for real in Australia's Queensland state in an advertising campaign that highlights how more firms are tapping the power of social media such as YouTube, Facebook and Twitter, for marketing.

Tourism Queensland hit on a winner with a global campaign to lure visitors to the Great Barrier Reef by asking people to submit online video applications for the best job in the world - caretaker of a tropical island for six months.

As news of the job advert on www.islandreefjob.com spread, 34,684 people from more than 200 countries submitted 60-second video applications, which everyone could see, for the $150,000 position on Hamilton Island.

It was just a great idea that captures everyone's imagination as they're sitting in a dreary office and it's raining outside, said Australian marketing analyst Tim Burrowes, editor of media and marketing website Mumbrella.

It was already very PR and publicity-friendly but because of all the promotion through videos and file sharing in social media the idea exploded into something much bigger.

Along the way Tourism Queenland, a government body, received a hoax application from Osama bin Laden, and admitted it concocted the story of a woman in a YouTube video who tattooed an advert for the Great Barrier Reef on her arm to win the position.

AGEISM, PORN, PUBLICITY

Tourism Queensland narrowed the list down to 50 applicants from 22 countries with one failed applicant, Canadian baby boomer Mandy Spottiswoode, accusing Tourism Queensland of ageism and only picking bikini babes or guys with washboard stomachs.

Tourism Queensland's investigation into claims that a finalist, Russian marine biologist Julia Yalovitsyna, was linked to a porn scandal kept the news flowing. She was barred from the contest, which reserved the right to exclude anyone found to have engaged in inappropriate, illegal or immoral behavior.

This Friday the list of candidates gets cut back to 11, including one wildcard entry voted online as the campaign's website tracks the contestants, like a reality TV show.

The finalists will take their places on Hamilton Island with the winner to be announced on May 6 and starting work on July 1.

Queensland Tourism Minister Desley Boyle said the worldwide response to the A$1.7 million marketing campaign had been phenomenal, generating more than $70 million in publicity value.

The campaign has largely relied on public relations and social networking activity, she said in a statement.

Burrowes said the best job in the world, designed by Australian agency CumminsNitro, would be held up as a case study of a successful social media campaign.

Another winner is a U.S. campaign by Doritos in which people send in video adverts for the corn chips, with the winning ad shown during the Super Bowl, U.S. TV's most-watched event of the year, and carrying a $1 million prize.

But even though increasing numbers of companies are trying to use the social media to promote their products, Burrowes said traditional media advertising still played a key role.

If you're a marketing director with a big brand and big budget you need to reach a lot of people quickly which means traditional media but you also have to now find a way to interact with social media. The best way is a combination, he said.

(Editing by Miral Fahmy)