There are several kinds of mail that can be sent. HATE mail is a type of mail that is sent with the intention of causing harm or distress to the recipient. JUNK mail is unsolicited mail that is usually sent in BULK and contains advertisements or other unwanted material. SNAIL mail is a term used to refer to traditional postal mail, as opposed to electronic mail. FAN mail is mail sent by admirers of a person or organization. AIR mail is a type of mail that is sent via AIR transport, usually at a higher cost than regular mail. BULK mail is mail that is sent in large quantities.