A few days ago, Paul Allen estimated that there are 1.7 million users on Google+, based on distribution data from the US Census Bureau. It was quite a creative solution, and should be reasonably accurate. Specifically:
Today I squeezed in enough time before and after our local parade, and before our Fourth of July picnic to update my model and do a much better analysis. I increased the sample size from 50 surnames to 79 (I would have done 100 but ran out of time), and I split out users from the US and from outside the US. I had to look at hundreds of profiles to determine US vs. non-US. Unfortunately, not everyone lists their location yet, so I had to infer it sometimes from their circles and language they were using. Sometimes I found them on other social networks and could resolve the question that way.
Google+ currently has 515,933 users in the U.S, and 1,226,136 outside the US for a total of 1,742,069 users.
Now he wants to take it further and try to estimate how many users may ultimately end up on the service. To do that, he’s put together a very short 5-question survey, and he promises to share the results of it when complete.
When we hear the results of it, we’ll be sure to let you know.