A reasonable person could have argued, and many did argue, that the "world does not need another social network" when Google+ launched.
Many predicted Google+ would fail. That doesn't seem to be happening. According to Experian Hitwise, Google+ not only has grown significantly since the summer 2011 launch, but has hit a record new peak of visitors in December 2011.
One hears almost nothing, in early January 2012, about Google+ "failing" to get traction.