E-mail clients using IMAP often leave messages on the server until the user deletes them. This allows multiple clients to manage the same mailbox - useful for support help desks for example.
IMAP is just one communications protocol on the web. Others include:
- Transmission Control Protocol (TCP) tcp
- User Datagram Protocol (UDP) udp
- Internet Control Message Protocol (ICMP) icmp
- Hypertext Transfer Protocol (HTTP) http
- Post Office Protocol (POP3) pop3
- File Transfer Protocol (FTP) ftp