Twitter turns eight years old today, and to mark the anniversary the social media site has launched a new tool, first-tweets.com, that enables users to look up their very first post to the site.

The new service also allows you to type in the name of any Twitter account, and find out what their first tweet was. Since its inception in 2006, the site has grown to over 241 million users, spanning 35 different languages.

The most followed account on Twitter is that of singer Katy Perry, who currently has more than 50 million followers, having joined the site in February 2009. The current top ten most followed accounts are all accessible via the new First Tweets tool.

Top ten most followed Twitter accounts and their first tweets

1 Katy Perry - @KatyPerry - 51.3 million followers

'Just got into Berlin... feeling better thank you, have my vicks inhaler by my bedside... and P.S. I GOT TWITTTTER! GAH. Such a follower!'

2 Justin Bieber - @JustinBieber - 50.2 million followers

'Check out my single "ONE TIME" on my myspace and spread the word for me. Thanks http://www.myspace.com/justinbieber '

3 Barack Obama - @BarackObama - 41.9 million followers

'Thinking we're only one signature away from ending the war in Iraq. Learn more at http://www.barackobama.com '

4 Lady Gaga - @LadyGaga - 41.1 million followers

'op rehearsing for my video just dance and am now at wmc to perform at the Armani and nervous records party. But I am no nervous record!...'

5 YouTube - @YouTube - 40.2 million followers

'Nearly 2m people check Usain Bolt celebration spoof video:http://tinyurl.com/5tv2jo '

6 Taylor Swift - @TaylorSwift13 - 39.7 million followers

'I love! RT @justinbieber I posted it!!! My response VIDEO to @taylorswift13 with an EXCLUSIVE SONG from my new album...ENJOY http://bit.ly/561XU '

7 Britney Spears - @Britney Spears - 36.3 million followers

'Welcome to Britney Spears' Twitter! Follow the latest in Britney news and get updates straight from Britney and her entourage.'

8 Rihanna - @Rihanna - 34.5 million followers

'The Wait Is Ova. 23 Nov 09'

9 Instagram - @Instagram - 31.2 million foillowers

'Hello there. We're just setting up our twttr.'

10 Justin Timberlake - @JTimberlake - 30.6 million followers

'Tennman Records released its first single today, Esmee Denters' "Outta Here. http://tinyurl.com/cs55pa . What do you think?'