Glossary

Quarantined emails are emails flagged as they make it to subscribers’ inboxes. Emails go into a “quarantine state” if a message looks partly spammy or potentially malicious, and the inbox service provider (ISP) in charge of placing the message in the reader’s inbox isn’t really sure. Here, subscribers have the power to move quarantined emails into their inbox or permanently delete it.

Senders can voluntarily choose to queue emails. This enables them to take advantage of asynchronous sending and optimize send time based on customer behavior. It also manages sending over an IP. If a sender sends a high volume of emails without warming up its IP, this might flag the message as spam content to ISPs.