All of us have been the recipient of irrelevant or personal email messages because someone, either inadvertently or with a false sense of importance, hits "Reply all" to a message sent to a group distribution list. It's annoying, but most of us simply roll our eyes, delete the message, and move on. But when it happens on a monumental scale, to a government agency, the consequences can be a bit more dramatic. Last week, the US State Department experienced a major interruption in email service caused when numerous users hit "reply all" to an errant email message mistakenly copied to thousands of recipients.

Numerous recipients of the initial accidental email sent back "reply all" email messages asking to be removed from the distribution list or asking that coworkers not use the "reply all" feature. Some tried to recall their initial replies, causing more messages to go to the group. All this extra email activity effectively caused a denial of service (DoS) on the department's communication system.

"Department staff hitting 'reply to all' on an e-mail with a large distribution list is causing an e-mail storm on the department's OpenNet e-mail system," says a cable sent to employees last Thursday by Under Secretary of State for Management Patrick Kennedy. The cable warns users of disciplinary actions if they use the "reply all" function for email with large distribution lists.

Of course, "reply all" is a very useful feature in many situations, and typically, "reply all" fiascos simply result in embarrassment (for the sender) or annoyance (for the recipient). But don't overlook the more harmful effects that can occur in some situations. It might be wise to caution your users to Stop, Look, and Consider before hitting that "reply all" button.

Do you have a humorous or annoying story about a "reply all" email? Or one that had serious consequences for your company? Do you have a related email policy in force? Let us know in the comments section below.