Happy Birthday Twitter: Seven Things You Didn't Know About Twitter

What was the most retweeted tweet of all time, who has the most followers and who made the biggest cock-up ever? Let's look back over seven years of Twitter...

1) Most retweeted tweet ever: Barack Obama's message on the night he won his second Presidential election is, so far, the most retweeted tweet of all time. He wrote: 'Four more years,' and posted it along with a picture of himself hugging first lady Michelle Obama. It was retweeted over 810,000 times.

2) Twitter is worth how much? Initially called Twttr and set up by Jack Dorsey in March 2006, the micro-blogging site predicts an ad revenue $540 million by 2014. Yikes.

3) Most followed person in Twitter: This honour goes to trousers-round-his-bum teeny bopper Justin Bieber. The singer's Beliebers have earnt him, at this moment in time, 36,305,545 followers. His most interesting musing of late? @justinbieber 'I wanna do a concert in space.' Lady Gaga follows Bieber in second place with 35,261,238 followers.

4) It's still growing: 11 Twitter accounts are created every second and one million Twitter accounts are opened every day.

5) Deepest tweet: On a dive to the bottom of the Mariana Trench in the Pacific Ocean, in a self-designed submarine, director James Cameron became the first person to send a tweet from 35,755 feet under the sea. He wrote: 'Just arrived at the ocean's deepest pt. Hitting bottom never felt so good. Can't wait to share what I'm seeing w/you.'

6) Biggest trending topic ever: On February 3, 2013, Twitter announced that a record 24.1 million tweets were sent the night of Super Bowl XLVII. That'll be the power of Beyonce.

7) Our favourite hashtag cock-up: When trying to promote Susan Boyle's latest album, her record label invited her fans to get the hashtag #susanalbumparty trending. It trended, but for all the wrong reasons.

CELEBRITY TWITTER ADDICTS