Google's social network was all a plan to get users to tie the bow around their information and package it to advertisers.
A report from the New York Times, breaks it all down:
The reason is that once you sign up for Plus, it becomes your account for all Google products, from Gmail to YouTube to maps, so Google sees who you are and what you do across its services, even if you never once return to the social network itself [...]
Thanks to Plus, Google knows about people's friendships on Gmail, the places they go on maps and how they spend their time on the more than two million websites in Google's ad network. And it is gathering this information even though relatively few people use Plus as their social network.
Google recently made changes to Google+ that linked it with YouTube, and now users need an account in order to comment and troll on their popular video sharing site. So, many people who didn't have a Google+ profile ended up getting one to continue business as usual on YouTube. Also, the company is pushing brands who have a Google+ account higher on their search results — an incentive to get them to sign up and post more content. This move, tying a less popular product with a popular one, has gotten Google in trouble with the Feds. "The Federal Trade Commission raised the issue during its recent antitrust investigation of Google, according to two people briefed on the matter. That investigation closed without a finding of wrongdoing," the Times reported.
Thus proven once & for all: Google+ has no use for users, but users are being used by Google. Google admits it. http://t.co/wBleoeKrC2— Rafat Ali (@rafat) February 15, 2014
As Bradley Horowitz, vice president of product management for Google+ puts it, "Google Plus gives you the opportunity to be yourself, and gives Google that common understanding of who you are."
And Google knowing more about you doesn't really do much for you, unless you do your shopping through ads in website sidebars.