Early in my mother's email career at Cornell University, someone accidentally sent a rather embarrassing personal reply to a mailing list she was on. She was quite taken with the situation, and since then, whenever a story of misdirected email is told, she comes out with one of her favorite sayings: "Never put anything into email that you wouldn't want to appear on the front page of the New York Times."
It turns out that you don't even have to make an addressing mistake for this to be true, as is amusingly related in Randall Stross's New York Times article "They Criticized Vista. And They Should Know." Stross relates quotes from users unhappy because their new PCs, advertised as being "Windows Vista Capable" via Microsoft stickers, can't actually run all versions of Vista and have numerous other problems with the latest version of Windows. But the catch is, these complaints aren't random Internet users moaning into the ether of a public discussion forum. Instead, they're written by Microsoft executives and are internal email discussions that have been subpoenaed as part of a class-action lawsuit complaining that those "Windows Vista Capable" stickers were misleading.
At least one of the Microsoft executives had an opportunity to learn from my mother's favorite saying. Steven Sinofsky, Microsoft's senior vice president responsible for Windows, was a student at Cornell in the 1980s. And how do I know this? He was Tonya's dorm resident adviser during her freshman year. Yes, it's a small world.
Ironically, my mother is now Cornell University Archivist, and I expect that contributions to the Cornell Archives will increasingly include email and other digital communications, just as they have for many years included personal letters. So consider the implications of what you write in email not only ending up in the New York Times, but also being preserved for posterity if the recipient donates his or her email to a digital archive.