Jack Dorsey is the co-founder and CEO of Twitter, the social networking site with more than 300 million users worldwide.

Twitter is a messaging system which limits users to 140 characters, but the company recently announced a small group of users are currently trialling tweets which use up to 280 characters.

[Read more: Everyone is making same joke about new character limit]

When did Jack Dorsey launch Twitter?

Dorsey co-founded Twitter in 2006, along with Evan Williams, Biz Stone and Noah Glass. The group managed to attract investment based on a preview build of the website that was put together in just two weeks.

What is Jack Dorsey's background?

Jack Dorsey was born in St Louis, Missouri, US in 1976. He studied at the state’s University of Science and Technology before transferring to New York University and then subsequently dropping out.

He worked as a programmer before moving to California and starting his first company in 2000; a firm which dispatched couriers, taxis and emergency services over the internet.

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However, he was inspired by the instant messaging services that were proving popular at the turn of the century so began to work on a web-based real-time short message and communication service that would eventually become Twitter.

Presumably then he was the first person to post on Twitter?

Yes, but strangely Dorsey’s account @Jack was actually the 12th one recorded on the system – the 11 prior to this were tests, so his was the first-ever official tweet.

What was Jack Dorsey's first-ever tweet?

On March 21, 2006, Dorsey typed a no-frills, straightforward message of: “just setting up my twttr”.

In 2016, he was temporarily suspended from his account for 15 minutes and on his return paid reference to this opening tweet, by signing back on with: “Just setting up my twttr…again (account suspension was an internal mistake)”.

[Read more: A timeline of Twitter's biggest moments]

Does Jack Dorsey have any other projects?

Away from Twitter, Dorsey created Square, a payment service which enables small businesses to accept card and contactless payments.

The service uses small, mobile card readers which connect to a smartphone or tablet to enable independent traders to accept other forms of payment apart from cash. Square launched in the UK in early 2017.

What is Jack Dorsey's net worth?

At the time of writing, according to Forbes he is worth $2.4 billion (£1.8 billion) and he is number 359 on the Forbes 400.

[Read more: Square launches in the UK]