Google’s newly rolled out social network Google+ has attracted around 20 million unique users during the first three weeks of its launch.

Last week, during Google’s second quarter earnings call, chief executive Larry Page said that Google+ had signed up its 10 millionth member.

According to the latest available figures, the number of unique users jumped to 19.93 million between June 29 and July 19.

Up until July 7, the growth of Google+ was slow, mainly due to the social network’s closed field trial. But, it soared after that, growing by two million every few days.

Meanwhile, Google+ has announced that it acquired a startup, called Fridge, to make the Circles service even better. Fridge developed a social network that let users to organize their friends into groups, share photos as well as plan events. However, neither Google+ not Fridge disclosed the financial terms of the deal.

Google+ is web search giant’s latest attempt to challenge social networking rivals, such as Twitter and Facebook, which have more than 300 million and 750 million users respectively.