More than one-third of professionals in UK sign up to LinkedIn network

LinkedIn, the social networking site aimed at professionals, has hit a milestone of four million members in the UK, it revealed yesterday, adding a million in less than eight months.

The group, which runs "a place for serious business people to do serious business", said that more than a third of professionals in Britain are now members of the site. It added that a quarter of FTSE 100 companies actively use the site for recruiting staff.

Kevin Eyres, the managing director of LinkedIn's European operation, said yesterday that growth in the UK was driven by "the increasing realisation that an online professional profile is the best way to present yourself publicly because of the opportunities that come your way".

The UK is one of LinkedIn's core markets outside of its domestic operation in the US, where it has 35 million members. It now has more than 70 million users across more than 200 countries, five million of whom are in India.

LinkedIn was set up by the internet entrepreneur Reid Hoffman in December 2002 and was launched five months later in Mountain View, California.

Mr Hoffman, who has invested in Facebook, Flickr and the social gaming group Zynga, became the chairman after four years as the chief executive of LinkedIn. The former Yahoo! manager Jeff Weiner was appointed to the chief executive role in June 2009.

LinkedIn turned profitable in 2007, the same year it hit one million members in the UK. It secured funding from several venture capital firms, which paid $53m (£36m) for a 5 per cent stake in June 2008, valuing the group at $1bn (£690m).

The site makes its money from three operations. It charges for premium subscriptions, advertising on the site and licensing software to its clients.