Google is linking its popular Gmail product to Google+, making it a requirement that new users also sign up for a profile on the network. Google is telling reporters that the move, first spotted by the Google Operating System blog, is part of a larger push to streamline and update its sign in procedures and better integrate its products. The move also spotlights the growing questions about Google+'s user base—more specifically, the engagement of the user base.

Currently, Google is counting 90 million uses in its Google+ network, a significant number considering the network is less than a year old. However, it has been somewhat obtuse in revealing engagement metrics, writes eWeek.  In Google's recent earnings call, it noted that CEO Larry Page said that "+users are very engaged with our products–over 60 percent of them engage daily, and over 80% weekly."

This figure called for additional clarification from Google Senior Vice President Vic Gundotra, eWeek said—namely that 60% of Google+ users sign in to use other Google products, such as Gmail, YouTube, etc. each day and 80% of + users sign into Google to access those apps at least once a week.

Or as All Things Digital put it: "So, if you registered for Google+ any time since it launched this summer, and you used any other Google product–say, search!–in the past day or week, while signed into your Google account, you got counted in those percentages."

Still the Network to Beat

Facebook is clearly still the social network Google+ has to beat–and by a huge margin. One measure that illustrates this: a comment on a Facebook post containing a link results in almost 5 times the amount of clicks of that link than a like of a comparable post, according to EdgeRank Checker. For every like a post gets, its link receives on average 3.1 clicks. Meanwhile, for every comment a post gets, it receives on average 14.7 clicks. Overall clicks per impression were found to be 0.005.