2009 was the year that micro-blogging service Twitter came of age as both a source of news and a way to chat about events historic and trivial.
Here BBC News looks at some of the topics that made waves in the Twitterverse and the news stories around them.
Barack Obama was sworn in as the 44th US President
On 15 January a
US airliner ditched
into the Hudson River in New York City.
was, inadvertantly, one of the first on the scene: "There's a plane in the Hudson. I'm on the ferry going to pick up the people. Crazy."
He went on to capture an
of the downed plane on his phone, which was passed around the site and used by news organisations around the world.
All 155 passengers survived the crash.
Also on 15 January, Apple chief executive Steve Jobs announced that he would
take medical leave
to write: "Apple without Steve Jobs is Sony."
Five days later, Barack Obama made history when he was
as the first black President of America.
Huge crowds turned out to see the event in Washington DC.
Twitter continued to be a major channel for the Obama administration, which had used it during the campaign to spread messages.
Waterproofwrote: "For the first time in my life I feel proud to be an American.
The February fires were the deadliest in Australia's history
raged in south-eastern Australia, destroying entire towns and devastating communities.
The fires were the deadliest in history, claiming more than 200 lives.
On 09 February maenad_au wrote: "Whoa. Just found out that friends who moved to Kinglake lost their home but were among the 'lucky ones' who got out alive."
The shooting began near the Gaddafi stadium
On 3 March, gunmen
a bus carrying the Sri Lankan cricket team on its way to play in the Pakistani city of Lahore.
The masked men killed six policemen escorting the Sri Lankans and a driver. Seven players and an assistant coach were wounded.
wrote: "Feeling extremely sad. The Sri Lankan national cricket team has been attacked in Pakistan."
Two weeks later, a
coup in Madagascar
forced out President Marc Ravalomanana and installed opposition leader Andry Rajoelina in his place.
The events led
to tweet: "Madagascar-ok coup d'état is done, what do Malagasy think will happen now?-the poverty and gulf between the poor and rich is still there."
At the beginning of April, Twitter made
during the G20 Summit.
Protesters, politicians and activists used the service inside and out of the meeting.
tweeted: "crowd still around bank of england surrounded by riot police - lots of people trying to negotiate police blockades to get home."
The service was also used to record a
in Central Italy. On 6 April
tweeted: "80Km from L'Aquila, felt earthquake strong and long. All nominal in Rome. L'Aquila is destroyed."
More than 300 people died, around 1,000 people were injured and 17,000 were left homeless following the quake in the Abruzzo region.
Twitter has continued to prove its worth during earthquakes in the year, with the US Geological Survey (USGS) using it to get
instant public reaction to events.
New cameras were installed on the veteran telescope
In May, the US Centers for Disease Control used Twitter to highlight growing concern over
wrote: "Travel Warning: Avoid Nonessential Travel to Mexico."
Later in the month, Nasa astronaut
was the first to tweet from space when he wrote: "From orbit: Launch was awesome!! I am feeling great, working hard, & enjoying the magnificent views, the adventure of a lifetime has begun!"
Mr Massimino was part of a successful mission to
fix the Hubble Space Telescope.
June was dominated by revelations about MP's
after they were published online.
Thousands of people ploughed through the data looking for irregularities and peculiar claims.
was one, writing: "Having a late night expenses trawl. Mark Fields, £250 on 'Consulting services regarding avatar/virtual personality/communications project' ?"
also found the exercise useful.
"Just spent some time exploring our local MP's expenses, and we've come to the conclusion that our MP is possibly the last honest one left," she wrote.
In Iran, Twitter became part of another
As other means of communication with the outside world were cut, protesters used the service to vent their frustration at the re-election of Mahmoud Ahmadinejad.
It also gave news organisations vital insights into what was happening on the streets of Tehran.
The pop singer collapsed in Los Angeles
On 14 June,
"I'm sorry I can't tweet anymore it's 3:40AM in Tehran and I'm exhausted and heart-broken. Hope tomorrow things'll get better. Good Night."
The end of June was dominated by headlines and tweets about the
death of pop star Michael Jackson.
Twitter became one of the main channels for updates after celebrity website
TMZ broke the story.
Twitter co-founder Biz Stone told the LA Times: "We saw an instant doubling of tweets per second the moment the story broke".
Michael Jackson's name became one of the top "trending topics" of the year on the site.
wrote: "Upset about Michael Jackson. The 13 yr. old in me still loved him. The 37 yr. old me wanted to see him complete his transformation."
was one of many who used Twitter to express their feelings about the death.
"Michael jackson? Dead at 50? I am filled with sad," he wrote.
During a hot, dry summer in the south-east of England Wimbledon got under way. It concluded when Roger Federer beat Andy Roddick to record his
15th Grand Slam
Mozilla first released Firefox in 2004.
The match meant that the 27-year-old surpassed Pete Sampras's total of 14 major titles. The marathon five-set match led
to write: "Today we witnessed an epic Wimbledon final. History to Federer, grief to Roddick, who played his best Tennis ever."
At the end of the month, another record was set when the Firefox browser passed
one billion downloads.
announced the milestone: "Firefox reached 1000 million downloads on 2009-07-31 15:00 UTC."
August on Twitter in the UK was dominated by a campaign to defend the NHS after critics of Barack Obama's health reforms described the NHS as "Orwellian" and "evil".
Gordon and Sarah
joined more than one million people who posted messages of support as part of the welovetheNHS campaign. People also added badges to their profile pages.
wrote: "welovetheNHS - more than words can say".
Tory MEP Daniel Hannan also faced fierce criticism from tweeters after saying he "wouldn't wish" the NHS on anyone.
Later in the month Twitter was used to distribute information during the Afghan elections.
Mr Karzai's was stripped of an outright win
"Taliban storm police HQ in Jalalabad; 2 police & attacker killed," wrote
the Twitter feed of the Afghan Pajwhok news agency.
The organisation used Twitter to quickly publish snippets of information before, during and after the vote took place.
was marred by widespread and deadly Taliban attacks and patchy voter turnout.
President Hamid Karzai was eventually declared Afghanistan's elected president for a second term amidst claims of serious fraud.
CBS News White House Correspondent
was one of many journalists who used Twitter to cover stories throughout the year.
On 10 September he tweeted from the White House: "WH spksmn Gibbs says Obama told PM Brown that he still thinks it was a mistake for Scotland to have released al-Megrahi."
Abdelbaset Ali al-Megrahi was jailed for the 1988 Lockerbie attack, which claimed 270 lives. He was freed on compassionate grounds by the Scottish government.
Singer Swift did not finish her speech
Celebrities also turned to Twitter to voice their thoughts on events.
lead singer of the band Good Charlotte, used Twitter to voice his annoyance with rap star Kanye West, who
interrupted the acceptance speech
of singer Taylor Swift at the MTV Video Music Awards ceremony in New York.
"All i'm saying is Taylor Swift is a young chic and you just walk up and grab the mic," he wrote.
At the end of the month, twitter was dominated by chatter about the limited launch of Google collaboration and messaging tool
Many turned to Twitter to find other people who had been sent one of the coveted invites.
wrote: "I'm on Google Wave -- if you are on, join up and let's get geeky!"
In October details emerged of an injunction served to the Guardian and at least one other national newspaper. It was to prevent the press from reporting that the MP Paul Farrelly had tabled a Parliamentary question about the oil traders Trafigura and its solicitors Carter-Ruck.
Whilst the mainstream media had its hands tied, Twitter was soon awash with discussion about press freedom and the nature of the injunction.
Stephen Fry is a prolific user of Twitter
and the injunction was overturned, prompting Guardian editor
to tweet: "Thanks to Twitter/all tweeters for fantastic support over past 16 hours! Great victory for free speech."
One campaign was swiftly followed by another, as Twitter reverberated with anger over a Daily Mail column
on the death of singer Stephen Gately.
Thousands of people voiced their disapproval, joined by various Twitter celebrities including Derren Brown
to complain to the Press Complaints Commission.
The BBC's decision to allow BNP leader
Nick Griffin to appear on Question Time
also led to a torrent of discussion.
simonaneville wondered: "will anyone who might be persuaded by Nick Griffin's arguments actually be watching Question Time tonight?"
The end of the month was marked by news that celebrity Tweeter
leave the service.
"Think I may have to give up on Twitter. Too much aggression and unkindness around. Pity. Well, it's been fun," he wrote.
He soon changed his mind and returned to the service a day later.
used Twitter to applaud the
of a health bill by the House of Representatives.
Tiger Woods was a hot topic during November
"This is history," he wrote in a message that was later voted "tweet of the year" in the Open Web Awards.
Revelations about the golfer Tiger Woods
also proved popular in the Twitterverse.
Reports quickly picked up on the initial accident.
, a Twitter feed set up by a Dutch teenager as a hobby, was one of the first when it wrote: "Bulletin -- Report: Famed golfer Tiger Woods seriously injured after crash near Florida home."
The Breaking News site delivers breaking news to more than 1.5m readers and
was sold MSNBC.com
Others have continued to distribute information and discuss the details of Tiger Woods' private life.
His official Twitter feed,
however, has remained silent since 26 June when it announced his new website.
Organisations continued to find uses for Twitter as the year continued.
was the account for charity Progressio.
The charity attended the United Nations Climate Change Conference in Copenhagen (COP15) where, like many people, they were stuck in the
to get inside.
"Copenhagen blues and queues: freezing cold + never-ending line to get into conference centre... security is getting tighter by the minute!"
Although not as a direct result, the conference organisers also used Twitter to keep delegates and the outside world up to date with what was
happening inside the conference hall.
The campaign meant that Joe McElderry missed out on a number one
On 12 December,
wrote: "COP President: Progress has been made".
The power of social networks to distribute messages quickly and effectively was also demonstrated when an online campaign succeeded in putting the rock band Rage Against the Machine as the Christmas number one.
The band's single, Killing In The Name, sold 500,000 downloads
beating X Factor winner
Joe McElderry's The Climb by 50,000 copies to clinch the top spot.
was one person pleased with the result.
"RATM are now where they belong: in the rock pantheon alongside Cliff Richard, Rolf Harris and Mr Blobby," he wrote.