Every day we get mail with text like this at the bottom:

This E-mail and any of its attachments may contain [big company] proprietary information, which is privileged, confidential, or subject to copyright belonging to [big company]. This E-mail is intended solely for the use of the individual or entity to which it is addressed. If you are not the intended recipient of this E-mail, you are hereby notified that any dissemination, distribution, copying, or action taken in relation to the contents of and attachments to this E-mail is strictly prohibited and may be unlawful. If you have received this E-mail in error, please notify the sender immediately and permanently delete the original and any copy of this E-mail and any printout.

Why do people put those tags on their mail? And do they mean anything? I can’t answer the first question, but the answer to the second is definitely No.

A notice like this is basically an attempt to make a contract: they send you the message and you agree to keep it confidential. But, of course, you haven’t agreed to anything simply by receiving a message. A valid contract also requires Consideration, that each party gets something of value from the agreement. There’s no value from just sending someone a message.

Read the rest of this story at John R. Levine’s blog (based on US law, but the basics will be similar in other countries so as a guide it should still apply).