Glossary Archive

IP Pool is a set of IP addresses shared among multiple senders on an ESP; reputation is influenced by the aggregate behavior of all senders using the pool.

ISP  is a common (but informal) deliverability term used to refer to mailbox providers and their receiving infrastructure (e.g., Gmail, Yahoo, Microsoft).

Internet Service Provider / Mailbox Provider: organizations that provide email mailboxes and operate receiving infrastructure (e.g., Gmail, Yahoo, Microsoft).

ISP/MBP provides mailboxes and receiving infrastructure; ESP provides sending platforms/tools for bulk or automated email on behalf of organizations.

Abuse where bots submit many addresses into signup forms (often without CAPTCHA), flooding recipients and damaging sender reputation.

Ongoing maintenance to reduce risk by suppressing long-term inactives and persistently soft-bouncing recipients (hard bounces/complainers are typically auto-suppressed).

Third-party services that attempt to identify undeliverable addresses; results can vary due to verification limitations and should be used cautiously.

Reduced engagement caused by over-mailing or repetitive content, often leading to higher complaints/unsubscribes and lower inbox placement.

Collecting email addresses from public sources (often without consent) for sale or unsolicited sending—high-risk and typically non-compliant.

List health is the overall quality state of a list, including engagement recency distribution, bounce/complaint patterns, trap risk, and maintenance practices.