Twitter turns 9 today: Here's a list of the top 10 tweets that define its history

New Delhi: Twitter- the microblogging site that created a revolution with its simple 140-character style has completed 9 years today. Set up on March 21, 2006, Twitter has attained the status of a platform for social discourses and opinion building.

Celebrating the anniversary, Twitter's blog looked back at some of the landmark moments created by Twitter users that define their history.

Here's the list:

1.Co-founder Jack Dorsey Tweeted first, when the service was called "Twttr."

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2. Early user Chris Messina proposed the use of a hashtag to denote people at the same live event.

3.When the Mars Phoenix Lander found ice on Mars, NASA used Twitter to break the news.

4. Early user Janis Krums happened to be on a ferry when a plane went down in the Hudson River.

5.In a royal first, Clarence House, the Prince of Wales' private office, created a Twitter account to announce Prince William's engagement to Kate Middleton.

6. Up late one night, Sohaib Athar inadvertently live-tweeted the raid on Osama bin Laden's compound in Pakistan.

7. Before he appeared publicly to affirm his second presidential win, President Obama noted it on Twitter. And within hours it became the most retweeted for the year.

8.Two bombs shook the Boston Marathon - and the world. As news of the blasts and the manhunt spread, Twitter became crucial for journalists, police and citizens alike.

9.Twitter as the perfect companion to TV is evidenced by the most retweeted Tweet to date: @TheEllenShow's starry Oscars photo.

10.As news broke about the attack at the offices of French magazine Charlie Hebdo people everywhere turned to Twitter. @JoachimRoncin's Tweet soon became a rallying cry for free speech.