A housemate of mine once responded to our landlord’s E-Mail in a torrent of expletives. She meant her reply for me alone, but that dangerous Reply All button tripped her up and our poor shocked landlord got an earful.  Everybody has a similar story about the note that went to Jenny P instead of Jenny Q.  A few tricks will reduce your chances of making such embarrassing mistakes:

• Watch for growing recipient lists. With conversation-tracking E-Mail systems (like Gmail), forwards and CC’s can merge into the conversation and the recipient list.
• Avoid E-Mailing sensitive information. My housemate would have been much better off venting her frustrations in a lengthy heart-to-heart, not an E-Mail.
• When hitting “Reply All,” always ask yourself if your information would really merit an individual E-Mail to everyone on the recipient list.  If it doesn’t, reply only to the original sender.