LinkedIn, the world’s largest social network for professionals, has announced it will be acquired by Microsoft for $26.2 billion (£18.5 billion) – one of the biggest technology deals in history. To mark this, we reveal some of the most incredible facts about LinkedIn you’ve probably never heard before.

Reid Hoffman founded LinkedIn in 2003 when he employed a team of his old colleagues – Allen Blue, Konstantin Guericke, Eric Ly and Jean-Luc Vailland – from social network SocialNet and PayPal to work on a “new idea”.

Hoffman is well known for his astute investing in companies and brands that have started out as small start-up companies and developed into global sensations. According to the book The Facebook Effect, Reid actually arranged the first meeting between Mark Zuckerberg and Peter Thiel, which subsequently led to the first angel investment in Facebook.

The total number of members who had signed up to LinkedIn one week after launch was 2,708. This image shows an email from an internal contest where the team had predicted how many members they would have.

The largest number of members come from the US, where there are 128 million users; over a quarter of the total membership. There are also over 104 million users in Europe, 92 million in Asia and the Pacific, 60 million in Latin America, 18 million in the Middle East and Northern Africa, and 17 million in Southeast Asia.

Yep, over four people joined LinkedIn in the time it took you to read that headline. This figure was recorded in 2014, so there are now potentially dozens of people joining the site per second.

Unsurprisingly, a high proportion of the wealthiest are tech-savvy and use their resources wisely to grow their list of connections and subsequently keep their businesses making money. Just under half of millionaires are now using the network.

A year after launch, in 2004, this was its new office on the third floor of 1975 El Camino Real in Mountain View, California where its team took up just a small part of the overall building space.

And 12 years later, this is its new headquarters, also in Mountain View. LinkedIn also has US offices in Chicago, Los Angeles, New York, Omaha, San Francisco, Sunnyvale and Washington DC. International LinkedIn offices are located in Amsterdam, Bangalore, Beijing, Dubai, Dublin, Graz, Hong Kong, London, Madrid, Melbourne, Milan, Mumbai, Munich, New Delhi, Paris, Perth, São Paulo, Singapore, Stockholm, Sydney, Tokyo and Toronto.

Hoffman let some old colleagues use some of the extra space in one of the many LinkedIn offices to get their start-ups going. YouTube was one of them; the team worked in the same office as LinkedIn before moving on to San Mateo.

LinkedIn is quick to join the April Fool's bandwagon every year as it plays practical jokes on its members with witty changes to the site. In 2014, it issued a “Cats You May Know” page, which is said gave its “feline counterparts a chance to connect with other cats in their network”.

The firm offers a chance for employees to bring in their parents, also known as #biyp, so that they can spend a day in the workplace to learn more about what their children do (because the chances are most job titles are way too techy to explain).

Weiner was previously a Yahoo! Inc, executive, but joined LinkedIn in 2008 as interim president, with Reid Hoffman taking on the position of executive chairman of the firm.

Not only does LinkedIn own one of the largest social networks in the world, but it also owns a number of different companies such as Rapportive, Slideshaire, Esaya, Mumbo, Pulse.

A few years after his arrival, Jeff Weiner issued iPad minis out to everybody working for the company as a “small gesture of the company’s gratitude”.

Having an identity makes all the difference on LinkedIn as those profiles with photos are 11 times more likely to receive page views than those with an empty photo space.

LinkedIn is now one of the most popular locations for professionals to find work, advertise jobs, market their companies, build connections and keep in touch with old colleagues. As a result of this, there has been a constant surge in the amount of professionals using the platform.

The ratio of men to women on LinkedIn is pretty evenly split, but slightly more men continue to use the platform (56%) compared to women (44%).

Of all the skills, this probably wouldn’t be the first to come to mind, but apparently it’s incredibly desirable (if you know what it means then you’re probably halfway there).

It’s inevitable that CEOs have a decent amount of connections, given they’re likely to be connected with their entire firm, as well as people outside of it. But it seems 930 is about the average amount of connections for CEOs to have, often from all over the world.

We all have a habit of using clichéd words to describe ourselves on our resumes, and apparently we all do the same thing on LinkedIn. Some of the other most overused terms on the site are ‘track record’, ‘passionate’, ‘successful’, ‘driven’, ‘leadership’, ‘strategic’ and ‘extensive experience’. I’m sure we can all put our hands up to one or more of those.

A staggering 25 million access the platform every single day – this has increased drastically given the site has only had around 3,000 visitors across seven days when it first launched (when the site looked more like the image above)

The average social media user is worth around $100 (£70), but for LinkedIn, with a market capitalization of around $24 billion (£16.8 billion) and a user base of 300 million people, the per-user valuation stands at around $93 (£65).

Among the books published by LinkedIn’s founder Reid Hoffman are The Alliance, which is a guide to managing talent in the networked age, and The Start-Up You, which talks about how to adapt to the future, invest in yourself and transform your career.

Reid Hoffman is now reportedly worth $4.7 billion (£3.3 billion) and is the 341st richest person in the world.