Twitter posts impressive figures as it celebrates its fifth birthday

"Inviting coworkers". As a tweet it was neither informative nor terribly interesting, but as the first, sent by Jack Dorsey to colleagues at San Francisco web firm Odeo five years ago today, it launched a global phenomenon.

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.

The site, which simply invites people to say "what's happening" in 140 characters or fewer, was initially dismissed as a platform on which to share colossal amounts of information of very little value. Now, it is an internet giant and even its sternest critics would be hard-pressed to dismiss its significance.

"We just made history. All of this happened because you gave your time, talent and passion. All of this happened because of you. Thanks". So wrote @BarackObama to his followers on winning the US presidential election in one of the least banal tweets in the site's short history.

Six months later, an adviser to George Bush suggested the site should be nominated for the Nobel Peace Prize, for its role in organising protesters and documenting the crisis in Iran that summer.

"As much fun as we were having, there was always in the back of our heads the idea of the potential of something important coming from it," said Biz Stone, one of Twitter's founding members. "Even if we didn't say it out loud and talk about it. Because we were just getting started and we really had no place saying anything like that."

Since then, news of Michael Jackson's death first emerged on Twitter, via showbiz website TMZ, Prince William and Kate Middleton announced their engagement, and the astronauts aboard the International Space Station posted incredible pictures of the Earth from space.

Despite operating at a loss for most of 2010, the company, which now integrates advertisements with its website, is valued at $3.7bn (£2.3bn), and employs more than 400 people.

The Twitter effect

Top 5 most followed Twitter users:

1. Lady Gaga, pop star (@ladygaga) 8,888,671 followers

2. Justin Bieber, pop star (@justinbieber) 8,267,804 followers

3. Britney Spears, pop star (@britneyspears) 7,172,476 followers

4. Barack Obama, US President (@BarackObama) 7,067,708 followers

5. Kim Kardashian, reality TV star (@KimKardashian) 6,824,049 followers

Twitter spats

Amy Winehouse and Mark Ronson

@amyjademermaid ronson you're dead to me; one album i write an you take half the credit– make a career out of it? don’t think so BRUV (17 September 2010)

Kelly Osbourne and Dannii Minogue

@MissKellyO the best thing to happen to dannii's career was that my mother hated her she needs to shut her mouth and concenterate on motherhood! (19 September 2010)

Lord Alan Sugar and Chris Evans

Lord_Sugar @achrisevans u only got there as my readers could not get to the shops due to snow. Your readers work in the shops (7 December 2010)

Without shops, the people that work there and consumers that spend their cash there @Lord_Sugar would still be that miserable Alan bloke (7 December 2010)

Top 5 most influential UK Twitter users:

1. Sarah Brown, campaigner (@SarahBrownUK)
2. Richard Bacon, broadcaster (@richardpbacon)
3. Eddie Izzard, comedian (@eddieizzard)
4. Stephen Fry, actor, writer and comedian (@stephenfry)
5. Umair Haque, economist (@umairh)

Important/historic tweets:

@BarackObama We just made history. All of this happened because you gave your time, talent and passion... Thanks (5 November 2008)
Phoenix Mars Nasa spacecraft: @MarsPhoenix Are you ready to celebrate? Well, get ready: We have ICE!!!!! Yes, ICE, *WATER ICE* on Mars! (20 June 2008)
@HarveyLevinTMZ We have just got word that Michael Jackson has died… (25 June 2009)