3 ms·

Thanks for the reply. What rules?

• mfincham 5y ago
  It's basically like you described - an informally specified set of rules the various "big players" in e-mail enforce. There's some consensus about the things you "have" to do to participate in e-mail but it's generally not a black and white "do these things and you'll be fine" situation.
• CobrastanJorji 5y ago
  As an example, mailing lists are likely to have a header like "list-unsubscribe: <mailto:list@host.com?subject=unsubscribe>", which enables email clients like offer easy unsubscribe buttons.
  • ev1 5y ago
    As a note, this can also be a URL, and can also be used to verify humanness in actual spam and not actually unsubscribe, so in practice pretty much only "good known senders with partnerships" get it to appear.