"The Real Reason You Should Care About the Petraeus Affair: Privacy."

"If the CIA director couldn't keep his emails secret, neither can you."

"Now everything is kept in the cloud on Google and Yahoo's servers," says Chris Calabrese, legislative counsel for the ACLU. "That quirk of [The Electronic Communications Privacy Act of 1986] has become hugely important for Americans' privacy." Once you've opened an email or your Facebook account, you've provided your personal information to a third party. The government can then ask that third party—Google, Yahoo, Facebook, Friendster, or whatever—for your information, and they don't necessarily need a warrant. The Constitution protects you from unreasonable search and seizure by the government. It doesn't stop third parties from sharing personal information you willingly give them. Likewise, there's no warrant needed to acquire the IP addresses—unique identifiers that can usually be traced to specific geographical locations—of people accessing those email accounts. According to the Wall Street Journal, that's exactly how the FBI figured out Broadwell was behind the allegedly harassing emails that sparked the investigation that uncovered the Petraeus affair.

That's not all. All your emails that are more than six months old are legally treated as online "storage" and accessible with a court order or a subpoena to the online service provider. The providers can say no, but usually they don't...