Spammers rarely include contact information in their emails, so some spam filters look for this as an indicator of legitimacy. Include your organization's name, physical address (not just a P.O. box) and phone number at the bottom of the eNotice.
When an ISP receives a complaint about one of your emails or has questions about a mailing you have done, if your contact information is in it, the ISP may be more likely to assume your email is legitimate and try to contact you with questions or feedback rather than blacklisting you.
Additionally, if a recipient views your email as unwanted, having your contact information in there may result in him or her contacting you rather than the ISP.