The mail or post is a system for physically transporting documents and other small packages, as well as a term for the postcards, letters, and parcels themselves. A postal service can be private or public, though many governments place restrictions on private systems. Since the mid-19th century national postal systems have generally been established as government monopolies with a fee on the article prepaid. Proof of payment is often in the form of adhesive postage stamps, but postage meters are also used for bulk mailing. Modern private postal systems are typically distinguished from national postal agencies by the names "courier" or "delivery service".

.mail is a generic top-level domain proposed by The Spamhaus Project in 2004, but unapproved by ICANN. Its purpose is to enable responsible message recipients to reliably and efficiently identify and accept spam-free mailstreams.

atmail is a commercial Linux messaging platform provider. The company was founded in 2001, counts 25 employees and has its company headquarters located in Peregian Beach, Australia. The company develops webmail, mail-server and groupware solutions built for Linux and other Unix operating systems, and includes the source code under a commercial license.