E-mail security policies

According to a survey by Webroot, some of the more common e-mail security policies have to do with prohibiting access to personal e-mail accounts from the office or stowing away corporate e-mails to such accounts. The next common strategy is to enforce a global confidential signature, essentially a signature that is automatically appended to all outgoing mails stating the corporate confidential policy.

Email Security Policies

What other security policies would you advocate where e-mail is concerned?

[Numbers published in Information Security , May 2008 Issue. Original Source: Webroot survey of 1,494 organizations]