The director of the C.I.A., David H. Petraeus, resigned last week after the Federal Bureau of Investigation discovered he was having an extramarital affair. The F.B.I. began by investigating a civilian e-mail harassment case, but, as the bureau reviewed thousands of pages of private e-mails, the scandal widened - to General Petraeus and others. While this scandal raises many questions about ethics, it also raises questions about online privacy and expectations of privacy. How careful are you about what you post and write on the Web? In "Online Privacy Issue Is Also in Play in Petraeus Scandal," Scott Shane writes: The hazards of the Web as record keeper, of course, are a familiar topic. New college graduates find that their Facebook postings give would-be employers pause. Husbands discover wives' infidelity by spotting incriminating e-mails on a shared computer. Teachers lose their jobs over impulsive Twitter comments. Are you careful about what you say in e-mails, or instant or text messages, that might be preserved or forwarded to others? How thoughtful are you about what you post on social media? How much do you think about the fact that anyone might see your posts? If a college or employer was searching for information about you online, would you be "Googled well"? What might they find? How well do you follow the general rule not to say anything online you wouldn't want everyone to read?