On the face of it, there is nothing particularly remarkable about a 19-second YouTube clip called Me at the Zoo. A young man stands in front of an elephant enclosure and delivers the following words: "The cool thing about these guys is that they have really, really long, um, trunks and that's cool. And that's pretty much all there is to say."
Inane words, yet significant because this video -- dated April 23, 2005 -- is the first ever uploaded on YouTube. The person speaking is the site's co-founder, Jawed Karim, the German-born entrepreneur who turns 30 this year.
When he posted that test-run clip, Karim could hardly have predicted just how huge YouTube would become. Sketchily devised a couple of years earlier by Karim and his friends Steve Chen and Chad Hurley during a dinner party at Chen's San Francisco loft, the domain name was registered five years ago this week, and officially went live in December 2005. But despite the trio's success at PayPal, few expected the video-sharing site to be more than a passing fancy.
Less than one year later and YouTube was such hot property that Google spent $1.65bn acquiring it, making Hurley and Chen rich to the tune of $346m and $326m respectively, based on shares owned in the company. Karim's early input and subsequent role as "YouTube adviser" netted him a cool $64m.
Now it is almost impossible to imagine life without YouTube. It is the third-most viewed website, behind Google and Facebook, and far more popular than Wikipedia, Twitter or Amazon. Twenty hours of new video clips are uploaded every minute and it attracts more than one billion views per day.
"YouTube has become huge because it suits the instant-gratification times we live in," says blogger and technology consultant Damien Mulley. "You can put up whatever you what, when you want. It's very easy to use on a technical level, and that's helped empower people. It's also a major entertainment resource."
Mulley began his blog (mulley.net) in 2002 and was an early convert to YouTube. "I could see the potential of it straight away and it made blogging a whole lot easier in terms of embedding videos. It stole a march on Google Video because your clip would be posted instantaneously, while its rival vetted each one first and it could be days before your clip would appear."
Jack Murray, managing director of mediacontact.ie, believes YouTube has revolutionised business. "It's changed the game," he says, "from broadcasting to what I would call 'narrowcasting'. You can target your audience cost-effectively."
Last month, he used his YouTube channel to publicise an initiative called Good News Friday which encouraged public relations firms to send out 'positive' press releases to combat "doom and gloom" in the media and was heartened by the strong response.
Along with the playwright Micheál Lovett and video content specialist Richard Doyle, Murray made a short film called DJ Hip-Op: Growing Old is Optional, which has been viewed 13,000 times. A hilarious and heart-affirming skit, featuring a bunch of Dublin senior citizens rapping and throwing hip-hop shapes, it publicises the Age Action Ireland charity.
"We wanted to make something that people would enjoy watching but also had a strong message," he says. "It's been intriguing to see the numbers go up and up. It's probably the sort of video that people watch several times."
YouTube spokesperson Oliver Rickman believes the site has achieved its present dominance for the simple reason that "people love expressing themselves". He says the ease of use is a big factor in its appeal. "It's a very straight-forward way of sharing videos. Factor in the rise in broadband availability and the significant drop in the price of recording equipment, and it's little wonder that so much content is uploaded all the time."
Rickman is heartened by the stories of ordinary people becoming famous -- and in some cases very wealthy -- thanks to their use of YouTube.
"Look at Lauren Luke. She was a young girl from Newcastle who loved make-up and thought it would be a good idea to film herself putting it on. It became this huge word-of-mouth thing which other young viewers telling her how much they enjoyed her demonstrations.
"Now, she has her own newspaper column and make-up line . . . And then you factor in the YouTube Partner Programme which sees people getting a cut of the advertising revenue."
YouTube has allowed countless people their 15 minutes of fame. Take Jill Patterson and Kevin Heinz's wedding video. The American couple and their bridal party didn't so much walk down the aisle as sashay through the church to the beat of Chris Brown's rambunctious song, Forever.
Or how about the embittered rantings of Tricia Walsh Smith, the English wife of a Wall Street tycoon, who shared with the world the details of her husband's infidelities -- and shortcomings in the bedroom?
It has also helped boost the careers of established stars such as pop singers Miley Cyrus and Katy Perry, both of whom have seen their official music videos watched more than 50 million times. "It has also helped young bands secure record deals when they can point out the large number of views that their videos have attracted," Rickman says.
Unsurprisingly, the site has also tracked celebrities' most embarrassing moments. Just ask Pat Kenny. The broadcaster found himself lampooned in the comments section as viewers watched him squirm in the face of an intruder on The Late Late Show and the accusations of a disgruntled audience member on The Frontline.
While YouTube may be the largest video-sharing site by some distance, its continued dominance is by no means a given. "Look at MySpace," says Damien Mulley. "It didn't develop and now is nowhere near as popular as it was. Rupert Murdoch bought it and did nothing with it and Facebook took over. It's the same story with Bebo -- they rested on their laurels. YouTube could be a lot more innovative -- offering a facility for people to edit their own videos, for example."
While Mulley uses YouTube "a lot", he is increasingly drawn to a rival vimeo.com. "It's more appealing for hipsters and it seems to focus on quality rather than quantity. Generally speaking the videos are far more professional and slicker."
Oliver Rickman contends YouTube is constantly innovative. "Just look at the fact that 10 million people watched a live U2 concert on YouTube, and there will be a massive audience for our live coverage of the Indian Cricket League this summer.
"YouTube is not standing still."