What’s the difference between global unsubscribe and FBL suppression?

Global unsubscribe suppresses recipients who explicitly opted out through your unsubscribe link or preference center. They asked to stop receiving mail through legitimate channels.

FBL suppression removes recipients who clicked the spam button instead of unsubscribing. They did not use your opt-out process but told the mailbox provider they do not want your mail.

Both types must be honored, but they represent different recipient attitudes. Unsubscribers may have liked your brand but no longer want email. Spam reporters felt strongly enough to actively complain.

Unsubscribers politely decline future invitations. Spam complainers file formal grievances with authorities. Both should be removed, but complainers represent stronger negative sentiment.