# Subscriber list management

*Marketing*. The validation that subscribers found in your contact lists remain active and engaged with your email marketing.

Email senders should review the engagement of subscribers and take action to [verify their interest][recon] or remove them from your lists.

Repeated sending of email messages to subscribers who have [unsubscribed][unsub] or [marked your email as spam][spam report] damages your [reputation][ers]. Damage to [reputation][ers] eventually impacts [deliverability][].

Never buy email lists or engage in [email harvesting][].

[recon]: /docs/sendgrid/glossary/reconfirmation

[deliverability]: /docs/sendgrid/glossary/deliverability

[spam]: /docs/sendgrid/glossary/spam

[spam report]: /docs/sendgrid/glossary/spam-reports

[ers]: /docs/sendgrid/glossary/email-reputation-score

[unsub]: /docs/sendgrid/glossary/unsubscribes

[email harvesting]: /docs/sendgrid/glossary/email-harvesting