Snail mail and smail (from snail + mail) — named after the snail because of its slow speed . It is a retronym that refers to letters and missives carried by conventional postal delivery services. The phrase refers to the lag-time between dispatch of a letter and its receipt, versus the virtually instantaneous dispatch and delivery of its electronic equivalent, email.
Snail mail is also known, more neutrally, as paper mail, postal mail, land mail, or simply mail and post.
Some online groups also use paper mail through regular gift or craft hot topics. In some countries, services are available to print and deliver emails to those unable to receive email, like people with no computers or Internet access.
Snail mail penfriends or snail mail pen pals are those people that like to communicate with one another through the postal system, rather than on the Internet which has become the more common medium these days. These kind of pen pals usually start their friendship by sending mails to eachother. After they progress in their friendship they can start post card exchange or even send gifts to each other.