There are (upto) 5 new optional mailing list fields called Tags. They do nothing other than record miscellaneous data you may wish to keep. To activate these fields they need to be named in the Mailing List Defaults tab in the Company setup. Once named they will appear on the mailing list page under those names. You can also specify if each field is mandatory or optional. They will automatically appear on some reports but will have to be added to others, on an as-needed basis. On reports they will go by their internal names, Tag-1 through Tag-5. On the Data Select and Download the named fields will appear on the People/Miscellaneous tab, but when choosing the fields for output they will be named Tag-1 through Tag-5.
For those with multiple company codes the Mailing List Defaults only need to be setup under your Default company. The mailing list is unaware of multiple companies.