Happy 9th Birthday Twitter! Memorable Twitter Moments

On March 21, 2006, Twitter co-founder Jack Dorsey posted the world's first Tweet: "just setting up my twttr." he declared. The company's mission? To give anyone who wanted the power to share thoughts, stories, and information in an instant. All for free but in 140 Haiku-esque characters. And many were up to the challenge. According to Twitter, at last count, the site has 288 million active users. 500 million Tweets are sent every day, in more than 33 languages.

And who are the most followed people on Twitter?

Katy Perry @katyperry: 67 million
Justin Bieber @justinbieber: 61.7 million
President Barack Obama @BarackObama: 56.7 million
Taylor Swift @taylorswift13: 54.6 million
Lady Gaga @LadyGaga: 45 million
Justin Timberlake @Jtimberlake: 43.2 million
Rihanna @Rihanna: 42.3 million
Britney Spears @BritneySpears: 41.2 million
Ellen Degeneres @TheEllenShow: 41.1 million
Cristiano Ronaldo @Cristiano: 34.3 million