This has been circulating again over the last few days:
As it turned out, sharing was not broken. Sharing was working fine and dandy, Google just wasn’t part of it. People were sharing all around us and seemed quite happy. A user exodus from Facebook never materialized. I couldn’t even get my own teenage daughter to look at Google+ twice, “social isn’t a product,” she told me after I gave her a demo, “social is people and the people are on Facebook.”
It’s a year old, but it appears from the outside that it’s still probably accurate.