One of the most surprising revelations to come out of the Mark Sanford sexual affair with a woman from Argentina is the exposure of their romantic email correspondence. Let me be very clear: When you type an email, once you hit "SEND," you've lost control of that message. You have absolutely no idea where it will end up, who will read it, and how it might be used against you. Attorneys will tell you that in a legal case, the first thing the other side demands are your emails. And once that's requested in a legal case, it's illegal to destroy them. Even the most innocent emails read out of context can be very destructive, and few things have ruined careers more than the exposure of email messages.

Be very careful with an email. Never criticize people, or handle anything sensitive through an email. Negotiate, argue, or fire someone face to face. If I need to share some personal or sensitive information with a client, I make a phone call. Be careful with jokes or course conversation.

This isn't legal advice, and I always encourage you to get good counsel. But from my perspective, other than critical business emails that you need for confirmation, records, or backup, I would consider deleting nearly everything else.

Bottom line: Never put anything in an email that you wouldn't feel comfortable about being read in public.