"Officially, Google declared that “sharing is broken on the web” and nothing but the full force of our collective minds around Google+ could fix it. You have to admire a company willing to sacrifice sacred cows and rally its talent behind a threat to its business. Had Google been right, the effort would have been heroic and clearly many of us wanted to be part of that outcome. I bought into it. I worked on Google+ as a development director and shipped a bunch of code. But the world never changed; sharing never changed. It’s arguable that we made Facebook better, but all I had to show for it was higher review scores."
A very interesting read by a former Google employee: