According to data collected by GlobalWebIndex, Google+ has skyrocketed in the past few months and can now boast over 150 million actives users.

From GWI:

When we looked into it further, we didn’t find anyone else who had any type of figures and Google has been suspiciously quiet since their Q3 financial statement that gave us that 40 million user number.

We did find, however, anecdotal evidence that supports GWI findings on the active Google+ user base. Firstly, there was this conversation with Don Dodge, a Developer Advocate at Google, where he states that “Any numbers you’ve heard are way low.” There are also people such as Paul Allen who are tracking the numbers of last names on Google+ to estimate subscriber figures. Allen says that Google+ subscriber numbers were growing at 2 million a day in September 2011 based on his methodology, meaning there are much more than 40 million Google+ users.

Back in September, the aforementioned Paul Allen used his model to estimate that Google+ had 50 million users.

In November, he estimated that Google+ was attracting 349,000 new users daily.

If Google+ really has broken the 150 million active user mark, where does that place it in the realm of other popular social networks? According to GWI, in third place wordwide:

There have been a few things that have happened with Google+ that could explain the meteoric takeoff. YouTube and Google+ became more integrated, for one. YouTube got the Google+ hangouts feature, and Google+ got the YouTube search feature built onto the main stream page.

Google+ launched Pages for businesses, which has thus far been a success. Allen attributes the uptick in new signups to the pages launch.

Google also built Google+ signup into its brand new Android 4.0 Ice Cream Sandwich OS. The Galaxy Nexus just launched with ICS, and many other Android devices are in queue for an upgrade.

As Google continues to push Google+ and build it into all aspects of Google, the user count will only climb higher. Is it possible that by this time next year, Google+ could be closing in on Facebook-type numbers? Let us know in the comments.