5 years ago today, at 12.50pm Pacific Daylight Time (8.50pm GMT), on 21 March 2006, Jack Dorsey, Twitter’s co-founder and chairman, completed the first tweet, marking the point at which Twitter, variously dubbed a social networking service and a microblogging service, was born.

In its first 5 years, Twitter has woven itself into almost all major worldwide events: the news that a plane had crash-landed in the Hudson River; election protests in Iran; the rapid dispersal of the news of an 7.8-magnitude earthquake in China; updates from the ground about the terrorist attacks in Mumbai.

There have been less important moments – multiple billions of them, including Stephen Fry being stuck in a lift (“we could be here for hours. Arse, poo and widdle”); the race in 2009 between Ashton Kutcher and CNN to be the first past 1m followers (a contest rendered irrelevant by Charlie Sheen’s meteoric rise this year); Sarah Palin’s coinage of “refudiate”; and Clarence House announcing the engagement of Prince William and Kate Middleton.

It took three years for Twitter to gain a billion “tweets” – messages of up to 140 characters. Today, more than 200 million users post that number every week.

Twitter has become an endlessly flowing river of news, opinion, information, expertise, contacts, data, links, connections. You can not only find out what is happening, but can directly connect with the people who want to connect with you. And this connection is the holy grail for marketing and media agencies everywhere.

Twitter has changed the relationship between companies and consumers. And links to stories broadcast on Twitter are a new source of incoming web traffic for organisations – though presently far behind Facebook or Google.

The question now is: where will Twitter be in five years’ time? What will Twitter look like at age 10? How far will its influence spread? Twitter is only getting bigger and more pervasive – and will become all-important to companys’ online marketing plans with a much higher take up rate for new & existing companies trying to establish a foothold in their markets. Whilst it is still struggling to find profitability, it still generated $45m (£27.7m) of revenues last year.

Presently 40% of tweets originate on a mobile device, a clue to its enormous usefulness; its text message-length 140-character format made it the first widespread web service to break free of the PC. And with 5.3 billion mobile phone users in the world, and 90% of the world’s population in reach of a mobile network, Twitter has a far better chance of reaching everyone sooner than Google or Facebook.

So, we say Happy Birthday, Twitter. Many happy returns! We look forward to watching you grow.

And, for anyone who reads this and would like to follow Design Inc on Twitter, you can find us at http://twitter.com/DesignincUK