Someone already suggested dynamic filter creations and it's an amazing idea. I want to expand it and suggest something similar for newsletters.
The pop-up saying "This message is from a mailing list should include 3 actions, and after one is selected, the pop-up should never appear again for that newsletter:
- Accept
- Unsubscribe
- Filter (this prompts the user to select what to do with these emails like in the filter creation flow and automatically creates a filter for the newsletter)