Thanks to the massive emphasis on Author Rank and Authorship, Google+ was hailed by many experts as one of the biggest content marketing trends to watch in 2013.
A cursory search on Alexa reveals that Google is #1 in traffic with Google+ comprising more than 8% of their total traffic.
To put that into perspective, Facebook ranks #2. YouTube ranks #3. Twitter ranks #12. LinkedIn ranks #14. Instagram ranks #60.
According to Business Insider May 1, 2013, Google + has now surpassed Twitter, in terms of active users. They report that Google+ now boasts 359 million active users, up 33 percent from 269 million users at the end of June 2012, according to GlobalWebIndex.