Matt Harding‘s silly dance that he devised in a Brisbane office block has not only turned him into YouTube‘s most enduring star – it has also made him a global marketing success that includes the lucrative speaker circuit and a book that is scheduled to appear in May 2009 (a collection of anecdotes about making his videos).

According to a report in the Age newspaper, unlike most viral web hits Harding’s popularity has increased with time.

His 2006 video took a little over two years to reach 10 million hits but the latest one passed that mark in 83 days. Both were sponsored by a chewing gum company.

Now Harding, 31, is the face of a new global marketing campaign by Visa, which has been running since late last month on television in eight countries, including Australia.

He has also been hired to appear in several travel agency advertisements and by Google to create a new layer for Google Earth, showing off his favourite dancing locations.

“Speaking has become an unanticipated side occupation that I very much enjoy. I’m not very good at it, but I’m learning a lot,” Harding has written in his online journal after returning from a speaking engagement at a gathering of animal-feed salespeople in Minneapolis.

But that’s nothing compared with the travelling the pair did for Harding’s latest YouTube video, which went up five months ago and has already garnered 13 million hits.

For the 4.5-minute clip, Harding spent 14 months travelling to 42 countries. He did his geeky jive with Bollywood dancers in Gurgaon, India, with humpback whales in Tonga, with lemurs in Madagascar and even in zero gravity in Nellis Airspace, Nevada in the US.