On a blustery October morning in San Francisco, a quietly spoken young man with Homer Simpson stubble and an oddly intense gaze is waxing poetic about the popular social networking site Twitter.
"I pretty much use it every day. My entire family is on it. My mother, my dad, my brothers. It's one of the ways we stay in touch. I don't live in my home town of St Louis, Missouri, any more, but my mom hears from me every day. And I hear from her everyday. It's a really fun way of staying close to your family and the people you care about."
These are sentiments with which the majority of Twitter's near 200 million users will heartily concur. Jack Dorsey, though, can claim a particular insight into the global success of Twitter, which has helped organise political resistance movements, rescue missing pets and wage celebrity feuds. After all, he's the guy who created it.
"I use it every day and I learn a lot from it," says Dorsey, who's due to visit Ireland this weekend. "There is the 'tweeting' and updating side obviously. However, there are a huge amount of people who just read and consume all the tweets and learn from them. It enables everyone to have a lot of information."
In case you've been living at the bottom of a well for the last four years, Twitter is the super zeitgeisty social networking tool that lately has usurped Facebook as the buzziest of internet brands.
Inspired by the dispatching systems used by emergency services, couriers and taxis, twitter lets you 'broadcast' to the world via short (a maximum of 140) character messages. You can also 'follow' fellow users -- such as friends, family or celebrities -- or, without even signing up, simply keep tabs on other people's Tweets. Since the late 90s, web entrepreneurs have been telling us the internet is making the world a smaller place -- with Twitter, this might actually be true.
Launched by Dorsey and his business partners Evan Williams and Biz Stone in 2006, Twitter was initially derided as the ultimate ego enabler -- the stereotype was of early users chronicling what they'd had for breakfast and whether they had walked the dog yet.
Before long, though, Twitter was demonstrating culture-changing potential. A turning point was Iran's 2009 'Green Revolution', which outsiders followed in real time via Twitter.
Closer to home, Twitter has allowed web users track stories such as the 'Cement Gate' assault on the Oireachtas in real time, whilst Iarnród Éireann reunited a stray cat with its owner after putting out a Twitter alert. When Gerry Ryan died, the news, naturally, broke on Twitter.
Dorsey agrees the Iranian uprising was a watershed.
"The fact this conversation was happening in public and people were able to use tools we could all use and they were using it from the streets of Tehran, which is not a place a lot of us outside Tehran understand . . . that was hugely inspiring. And also brought us to the forefront of the conversation."
Twitter's other niche, arguably, has been as a facilitator for rowing celebrities. On her Twitter feed, Courtney Love has spent the last 18 months grandiosely heckling other rock stars. Lily Allen used the site to criticise Cheryl Cole. In a recent Rolling Stone profile, Katy Perry is portrayed devoting as much time to Twitter as to songwriting. Dorsey must have been shocked that celebrities have embraced the medium so enthusiastically.
'We did know it would be a great tool for anyone with a very public voice, you know, a public figure, because it allowed them to instantly reach out to whoever they wanted to and to be a lot more approachable. We were surprised however at how quickly it (celebrity tweeting) took off. Once a few of them joined,the rest seemed to follow."
Dorsey will speak at the Dublin Web Summit, a brainstorming session featuring some of the world's leading web entrepreneurs (the founder of YouTube and Skype are also attending).
He has never been to the country but is aware of its reputation as a technology hub. If anything, Dorsey seems rather more enthusiastic about Ireland's stature in the tech industry than many of Irish people.
Far from being a cheap outsourcing option (by dint of our low corporation taxes), he says Ireland is perceived as a good place to set up if you want to employ smart, resourceful people.
"It is generally seen as a place where exciting things are happening. What I know is that a lot of companies are looking at Ireland not for their back office functions but for a very focused research area. It is more focused around innovation and new ideas, as a centre to bring in a large European conversation."
Dorsey has strong opinions as to why the US -- in particularly the San Francisco-Silicon Valley area -- is an internet hotbed even as, for all our investment in the so-called 'knowledge economy', Ireland lags behind. In America, he says, it's okay to fail.
"One of the strengths of the culture in America is that people are happy to take risks and make mistakes and learn from them. I have friends in Paris and Italy. I don't think there is a culture of allowing for mistakes in Europe as much as there is in the US, where you can actually fall down and get back up and have another success. I don't think that's as tolerated outside the US."
Plus, it's much easier for start-ups to attract funding on America's West Coast, where venture capitalist firms and 'angel investors' are in abundance.
"Having an idea is one part (of being successful)," he says. "Being able to work freely on that idea is a whole other thing. And that's where the angels come in. In Silicon Valley, they are willing to put in a little bit of money."
One prominent web entrepreneur who won't be at Dublin Web Summit is Facebook founder Mark Zuckerburg. The 26-year-old is understandably keeping a low profile, having been portrayed as an emotionally deficient anti-hero in the new David Fincher Facebook movie, The Social Network.
In fact, The Social Network has biting things to say about the web community, sketching the guys behind these companies as vengeful geeks determined to gorge on money and girls after years of being the underdog. As you would expect, Dorsey disputes such a portrayal.
"I think that's a very Hollywood view of start-up culture," he says tartly. "That's not reality at all"
While he lives modestly, Dorsey himself is almost certainly a millionaire many times over. Exactly how much he's worth is a matter of conjecture -- as a private company, Twitter doesn't have to open its balance sheet to the world, though it is conservatively valued at over $300m.
Just last year, it turned a profit for the first time, after agreeing a $25m syndication deal with Microsoft and Google.
This was a significant step forward as, for several years, it was uncertain if and how Twitter was going to make money.
Then again, it was by focusing on users rather than revenue that it was able to become a success in the first place, says Dorsey.
"You have to be able to do a lot of experiments and recognise the best product will come from the usage of the product," he says. "Models that are set up in the lab aren't going to help the network. These things take time and I think you have to be aware of that."