Atomic Top Level Domain Filter (ATLDF) is a software program that allows users to automatically select certain e-mail addresses from the list, based on the professional or national basis. When is it necessary and who needs it? Just a uncomplicated example - in edict to induce maximum homecoming from your marketing effort, you need to tear your mailing list into specific aim groups and optimize your message for each one. This is when ATLDF comes in handy, separating emails into these groups - for example, .edu zone for marketing to students and academia, .es for reaching the Spanish but, .com for contacting companies.