The "Undisclosed Recipients" property in Microsoft Outlook 2007 lets you send email to a group of users without disclosing email addresses. This is beneficial when you have a large group of recipients, and you don't want every recipient to view your email list.
The "Undisclosed Recipients" property lets you hide your email recipients. This is a courteous way to send email to several people, so the email addresses can't be harvested for spam.
The option to send to a group of undisclosed recipients is in the address book. You view and edit your list by clicking "To" in a new email message. Click "Undisclosed Recipients" and add and remove users. Click "OK" to add the list to your email.
Only you can see the list of recipients. You may receive several reply emails. When the user clicks "Reply All," the "undisclosed recipients" are added to the list of people for the reply. This gives your recipient an error, so they must remove the specialized group from the recipient list.