Whoever is the brains behind this is a genius. The 'Circles' feature is GREAT! You can create a few circles of people you know and each of the circle needs not know the other cirlces' members. Isn't this brilliant? This also means photos posted and shared with a particular group are not visible by the other circles. So, you don't need to worry that your boss will know that your college mate now works with a competitor of where you work. You may not want your boss to know so much of your family happenings with the photos that are posted. Or you just do not want to share so many things with your colleagues. No one will reject privacy. Way to go, Google!
Who says an accountant is only good at numbers?