Google+ is really two things. One is a destination for connecting with friends and subjects that interest them. When the press writes about Google+, it's usually in this context.
But Google+ plays a second role, as a product that improves other products. Google tends to talk about this in abstract terms -- it's "a social spine;" it's a "fabric;" it "weaves" Google products together. Let's try to be a little more concrete about what Google+ is doing besides giving people a Facebook alternative.