List Management

The acquisition-integrity angle on list building — Spamhaus's confirmed-opt-in baseline, the acquisition metadata every address should carry, and why harvesting software (illegal in AU/NZ/CA and elsewhere) and purchased/appended/co-reg lists are the root cause of poor list quality.

How mailbox-provider feedback loops (FBLs) work — ARF report structure, enrollment and vetting, and operational recommendations for feedback providers and senders.

The eight ways addresses end up on a mailing list — from confirmed opt-in to harvested — ranked by relationship ownership and complaint risk, with the acquisition rules that keep complaints down.

Exact syntax and semantics of the List-* header fields and the one-click List-Unsubscribe-Post mechanism, including DKIM requirements and why major mailbox providers mandate them.