LinkedIn’s member base is set to rise to 165 million users by the end of 2011.

That’s the conclusion of a new report by social media agency FreshNetworks. Having tracked LinkedIn’s growth figures over the last three years, it predicts that the company will be well over half way to achieving 200 million users by the end of the year.

This forecast follows the company’s first earnings announcement, published last week, which reported revenue up 120% to $121 million in the last quarter.

“LinkedIn has clearly upped its game in the last nine months, swiftly implementing site improvements in response to user feedback and market demand,” said Charlie Osmond, co-founder of FreshNetworks. “The LinkedIn proposition offers B2B businesses, who are often nervous of using other social media networks for business, the chance to network professionally. Increasingly, LinkedIn is also being used by recruiters and the growing LinkedIn community are spending more time on the site improving their profiles.”

LinkedIn itself estimates that around a million new members join its network every week, which equates to more than one member every second.