Bulk email without duplicates

Product Support
5

  1. Can we create a plugin that will work on our instance even if it is hosted by Discourse, or we need to host it?

  2. Then, for emailing, do I need to export the list created by the plugin?

  3. What would a plugin do? Can I create a kind of long list from within the Discourse server? Or the idea is to send info to another server?

Thanks