Mail Preference File. The names of those who do not want to receive direct mail solicitations. Other terms used internationally: Robinson list, pander file, suppression file. The Direct Marketing Association maintains a continually updated suppression file, called the Mail Preference Service, which is based on requests from consumers and available to mailers in various formats. The DMA also maintains an opt-out file for telephone solicitations, called the Telephone Preference Service, and will soon implement an Email Preference Service. (Also see "Opt Out.")