Manage Email Signatures centrally from your Desktop - For All Users

Jesper Frier

It is best to include disclaimers on internal as well as external emails, since the same legal issues apply to both.

Although the contract issues will mainly apply to external emails, the confidentiality and libel aspects will be just as important for internal email as they are for external mail.
For instance, there have been cases where employees sued their employers for emails with sexual or other offensive content circulating the office.

As for confidentiality, this might even be more of an issue for internal mail, since not only is there quite a good chance that a colleague might accidentally read a confidential email, an insider will recognize the importance of the information much faster than an outsider.