Google+ U.S. Users Number About 5 Million (or 9 Million)

Google+ has more than 5 million users in the United States alone during its first two weeks of existence, according to a couple of creative calculations by early users of the fledgling social network.

Open June 28 to limited field-testing, Google+ is Google's (NASDAQ:GOOG) major bid to bite into the massive growth and influence of Facebook, which has more than 750 million users and poses a threat to Google's display ad business.

Using the U.S. Census Bureau data on how many people there are in the United States with each surname, Ancestry.com founder Paul Allen calculated that there are about 4.7 million Google+ users (and growing). Allen's estimates, up from 1.7 million users July 4, do not include non-U.S. + users. "I updated about 1/4 of my surname counts tonight, and am very surprised at how fast the user base is growing," Allen wrote in a July 10 post on Google+.

Allen said he expects to have four times as much data when he updates his research July 11. A Google spokesperson declined July 11 to provide user metrics for eWEEK.

Allen's approach isn't the only armchair methodology. Atul Arora chimed in on Allen's thread that users can calculate the number of Google+ users by running a Google search for "inurl:plus.google.com/*about site:plus.google.com".

eWEEK received roughly 8,890,000 results for this query, suggesting that non-U.S. users are indeed factored into this search.

eWEEK is open to exploring additional methodologies where available.

Whether there are 5 million or nearly 9 million + users is up for debate; only Google knows for sure, and there's no benefit in its releasing its stats when the service is in limited testing (though it seems more and more people are finding their way in).

While it's fine for Google that Google+ is gaining traction, the question that remains is whether + has staying power. As in: Can Google keep up the + growth for several months or even a year?

If Google+ were to grow by 5 million a week for a year (ending June 28, 2012), it could have more than 250 million users, or roughly one-third of Facebook's current user base. Another question: Will Google+ persuade Facebook users to defect to the new social network in town?

If this is the case, Facebook will lose users and Google+ may catch the king of social media earlier than the current growth trajectory.