At last count, the 'Dublin Coastal Development' video announcing Seamrog [sham rogue] City, complete with beachfront villas and skyscrapers that looked suspiciously like London's Gherkin and BT Tower and the Bank of China in Hong Kong, had been downloaded at least 34,000 times on social networking website YouTube as of Friday lunchtime. That number grew about 10% every 12 hours over the last two days of last week. It was the 63rd-most downloaded video on YouTube last week.

In fact the spoof, which also promised a giraffe-only zoo as part of the development, was produced to promote the launch of Funda. ie, a property web portal that will compete with Daft. ie and Myhome. ie.

Dreamt up by creatives Ann Fleming and Nicole Sykes at Dublin ad agency Chemistry, with its 3D graphics by The Farm, the video was uploaded to social networking sites MySpace and Bebo as well as YouTube on Thursday 21 September, and quickly gained attention, featured by Monday on RTE television.

The production costs came to just 30,000, which for the "earned media" attention it has already received would be extremely good value for money.

"We were challenged with budgets, so we asked how we could do something that really got us attention, " said Sinead Cosgrove of Chemistry. "Ireland is at the tipping point of credibility on all things property."

Enough people were ready to believe that Sham Rogue City was for real that punters rang up looking to place deposits, she said.

This may have been helped, however, by the fake planning notices that were posted up around Sandymount strand.

"We even got calls from construction firms looking to partner up, " said Ronan Higgins of Funda. ie. The plans were similar enough to the fanciful 'World' archipelago of artificial islands off Dubai to be plausible, he said.

The video wasn't meant to leave people properly fooled, however.

"The giraffe-only zoo should have been a clue, " said Higgins, who before starting work with Funda had worked in California for a number of years and was familiar with viral marketing from previous jobs.

The video even sparked inquiries to the offices of the Progressive Democrats. The party's Dublin northside senator Tom Morrissey some months ago made a real-world proposal to transform Dublin Port into a forest of skyscrapers to rival Shanghai or Manhattan, which may have accounted for part of the confusion.

Chemistry, which won a gold at the Cannes Advertising Festival earlier this year for the copywriting on its 'Power of Press' campaign for National Newspapers of Ireland, said it plans to release more viral campaigns on an unsuspecting public as soon as possible.