A postcard is a piece of thick paper or thin cardboard, typically rectangular, intended for writing and mailing without an envelope. They are accepted as a form of mail worldwide and are often used to send a brief message along with a pretty image. Postcards are typically made from a piece of thick paper or thin cardboard, and its common to write a brief message on one side along with the delivery address while the opposing side dawns a pretty image. Postcards are often used when people are traveling and want to share a local view without writing a page-long letter. They are also used for marketing purposes, to share good news, or to spread the word about an upcoming event. Postcards come in different sizes, including 4" x 6", 4.25" x 5.5", 5" x 7", 5.5" x 8.5", 6" x 9", 6" x 11", 3" x 4", and 6.5" x 9.5".