Yes, Google+ has 170 million users, but just how active are they? A recent report from RJ Metrics suggests that based on public posts from 40,000 Google Plus accounts, engagement is poor. The average public Google+ post is seeing less than one +1, less than one reply and less than one re-share.
The article cites the fact that typically 70% of users re-post again when a public post has been made. However with Google+, of those users that make one public post, only 30% ever post again publicly.
Another interesting fact from the study was the number of total public posts made (categorized by when they made their first public post). The “post decay” is concerning as users are less likely to make posts just a few months after joining. After the initial leap of posts in the first month, the total posts slow to a trickle:
One big reason for this could be the fact that many Google+ users simply don’t want to use the network. While Google+ may have 170 million users, signs point to many being unused accounts. Anyone signing up for a Google+ service is required to create a Google+ account and they may try it out (making the 1st public post), then forget about it altogether.
One other additional item to consider about the data is that all information pulled was from public posts, no private data was analyzed. Google+ is a bit more sophisticated than other social networks, and may take a post or two for a user to get acclimated with the service.
For more information, see the full report from RJ Metrics.