Between June 29 and July 19, Google+ was accessed by 5.31 million people in the U.S., followed by 2.85 million in India, 0.87 million from the U.K., and 0.86 million from Canada. Unsurprisingly, China was missing from the top ten countries represented on Google+, though Taiwan had 0.52 million visitors. Click on the graph (right) for the U.S. vs. International breakdown.
Unique visitors measures how many people access a site, including non-Google+ members. But even if a Google+ user visits the network every minute, he (Google+ is 57 percent male, according to Hitwise) is only counted once. ComScore said it derived the estimates from an opt-in global research panel of two million.
Google+ should probably thank rival social networks for easing the way to broad consumer adoption. Twitter, launched in April 2008, spent months below the five million unique visitor mark before it quadrupled to 17 million in April 2009. Facebook hovered below ten million visitors until January 2008, nearly four years after it hatched; in May 2011 it hit 157.2 million visitors, according to comScore.
Meanwhile Hitwise took a magnifying glass to Google+'s U.S. traffic. In its first four weeks, most Google+ visits were coming from the Los Angeles, followed by New York City and San Francisco, it reported. It ranked #42 on its list of most visited social networking sites.
On Wednesday, Ancestry.com founder Paul Allen (not to be confused with the Microsoft co-founder) used a "new and improved" estimation tool to predict that Google+ has just under 18 million users.
Earlier this week Apple added the Google+ iPhone app to the App Store, and it quickly became the most popular free app.
For more, see the 15 Google+ Users You Should Add to Your Circles slideshow on your left.
If you're a Google+ greenhorn see PCMag's full hands-on with Google+, as well as 6 Things Google+ Can Do That Facebook Can't and Social Networking Showdown: 8 Facebook Features Google+ Doesn't Have (Yet).
More concerned about privacy? Check out Google+ Privacy: Has Google Learned Its Lesson?