After a strong start, Google+ could have lost its momentum, at least if we are to believe ComScore's numbers. "According to comScore, Google+ users averaged only three minutes on the site during January, a pittance compared to Facebook's average of 405 minutes per visitor."
That's a really low number, but I'm not sure it's accurate. Google+ is not a separate service like Google Finance or Google Scholar, it's the social fabric from many Google products. Below Google's navigation bar, there's always a share box and a notification button that lets you read comments and post your replies without visiting Google+. Google's search results include pages shared by your Google+ circles, YouTube's homepages shows videos shared by the people you follow in Google+ and many pages have +1 buttons. You're using Google+ even you're not visiting plus.google.com and that's because Google+ is an upgrade, not a new product.
"This is just the next version of Google. Everything is being upgraded. We already have users. We're now upgrading them to what we consider Google 2.0," says Vic Gundotra, Google VP.
Google's bet is so significant that Google+ simply can't fail. Google+ is just a fancy name for a new Google that knows more about you, so that it can offer a more personalized experience. Upgrading to Google+ will offer better search results, better ads, simple ways to share content, collaborate and communicate with the people you care about. It's the same Google made more powerful by a social upgrade.