Google+ expands circle of friends by 20 million

The Google+ social network has grown rapidly since it was launched three weeks ago.

"I've never seen anything grow this quickly," said Andrew Lipsman, an executive at comScore, which tracks Web traffic. Google+ has had 20 million unique visitors since its introduction, according to a comScore report released yesterday. Twitter was the fastest growing site when it quickly gained some 20 million visitors when it went public in 2009. "But that happened over several months," notes Lipsman.

The skyrocketing growth of Google+ is especially impressive since, at the present time, you can only join the social network by securing an invitation from a current member.