Here’s a better take on what Google+ is trying to do in relation to Facebook, from Dhanji Prasanna:
It might surprise you to learn that I don’t find Google+ all that innovative. It hits all the notes that a Facebook clone merits, and adds a few points of distinctiveness that are genuinely compelling, sure–but I don’t find it all that interesting, personally. To my mind, Twitter was a far greater innovation that continues unchallenged. But broad product innovation is not exactly what they were going for, I believe.
As I said in a previous post, The Answer to Facebook, Google+ is not meant to be a direct Facebook competitor/killer. It is a tool/service that people will use that may cause people to drift towards it for the other novelties that it has. But, the purpose of the two services do not overlap in all ways.