A mediumweight IMAP user base represents sophisticated enterprise users with login sessions lasting most of an eight hour business day. These users send, receive, and keep a large amount of mail. Furthermore, these users have unlimited or very large message quotas. Their inboxes contain a large amount of mail that grows during the day, and is fully or partially purged in large spurts. They regularly file messages into folders and search for messages multiple times per hour. Each concurrent client connection sends approximately eight messages per hour. These users send messages with an average of four recipients and have the same message size mix as the Heavyweight POP and Lightweight IMAP user bases.