The state of an email message being held in a sending system before actual transmission occurs indicates that the message is not immediately dispatched to the recipient’s mail server. This delay can be due to various factors such as server load, network congestion, or deliberate scheduling. For instance, a marketing campaign sending emails to a large recipient list might queue the messages to prevent overwhelming the mail server.
Queuing provides several operational advantages. It allows systems to manage sending volume effectively, preventing service disruptions and maintaining system stability. Historically, queuing mechanisms have been vital in handling large email volumes, ensuring delivery even during peak sending times. This approach optimizes resource utilization and improves overall deliverability rates by avoiding server overload and potential blacklisting.