Your Circles are never revealed to other Google+ users, but your friends are – by default. Depending on who you buddy up with or follow, that could be a bad thing. Fortunately, there’s a way to limit who can view your Google+ friends and followers. In the Privacy tab, under Sharing, click Edit network visibility. Simply uncheck the two boxes to hide (or selectively hide) who you’ve added to circles and conversely, those who’ve added you to their circles and keep your friends to yourself.