Google+ – Google's new social networking service – added about 25 million visitors in less than a month, according to data from ComScore.

In the month ending on July 24, Google+ saw over 6 million visitors from the United States, with India having more than 3 million visitors, ComScore said.

The growth was faster than what Facebook acquired in its early days, according to a report from The Los Angeles Times. At the beginning, Facebook was open only to colleges, and increased slowly by design.

Facebook since has seen stable growth among the varied social networking services, said Andrew Lipsman, ComScore's vice president for industry analysis. Now, Facebook has more than 750 million users.

Google+ was launched in late June by invitation.

It is a rival to Facebook for users and advertising.

It took Twitter several months to gain 20 million users.

However, there were some questions about the accuracy of the number of unique visitors to Google+ in its early weeks, reports SlashGear.

“I’ve never seen anything grow this quickly” Lipsman told The Wall Street Journal recently.

Also, Google did not market Google+ among users of Gmail and other site services. A few weeks ago, Google suggested that 10 million Google+ users were registered, SlashGear adds.

In a related matter, TechZone360 says that USA Today has reported that the U.S. Navy is looking into whether Google+ could be used by the service members, as well as their relatives and friends.

TechZone360 explains that Google+ could have a key security advantage over Facebook, Twitter and other social media sites because Google+ lets users create "circles," or groups of relatives, friends or work colleagues who have access to content. Members of the Navy would not need to be concerned about classified or personal information leaking out to the public, TechZone360 reports.