Some agencies have expressed opposition to the idea of allowing people to tag things privately, as that may imply that the agency condones the use of the computer and its resources for private purposes. Whatever is done, it will require considerable trust in employees and confidence in their abilities. It must be explicitly documented and must involve the training of every employee in what should or should not be tagged. It should be said that at least one specific study has shown that employee tagging is not very effective in practice unless it is routinely reviewed by supervisors. At the mail server level, all incoming and outgoing email that is of interest can be saved using specifically-designed filters to exclude that which is not of interest.
Outgoing email is far more difficult.
Some electronic mail may have more information than that, such as gateway timestamps, blind carbon copies, and more. Because any email transferred to the archives can be relied upon to have at least the four fields mentioned above, they form the basis of the metadata to be used in conjunction with the email record itself. This should be the subject line of the email, as given by the sender. Corresponds to the Dublin Core element Subject. Ideally, some means of indicating the records schedule under which the record should fall should be made part of the subject line, as suggested above in the discussion on employee tagging.