Google+ is more than just a Web destination, and Google is reaping the benefits from it already:
What's important about these aspects of Google+ is that they benefit the company and its customers regardless of whether Google+ ultimately wipes Facebook off the map. The social signals, personalization and improved ad targeting that Google+ creates are arguably by themselves enough to justify the entire effort from Google's perspective. It may be less compelling as a news story than a virtual death match between Mark Zuckerberg and Larry Page, but it's real.
Google+ chief Bradley Horowitz told me in an e-mail:
"Over the past decade, Google has come to provide the products and services that have become essential to internet users... not only Google search but also the Chrome browser, the Android phone, YouTube, Gmail... the list goes on and on. Google+ was designed from its inception as a foundational, unifying layer that makes these already great services even greater. So Google+ is different. It's not only an innovative new social network, it is also the identity, relationship and interest system for Google."