Postcrossing

Postcrossing is an online project for people to exchange postcards with other project members globally. The project's tag line is "send a postcard and receive a postcard back from a random person somewhere in the world!" The name Postcrossing is a union of the words postcard and crossing, and its origin "is loosely based on the Bookcrossing site".

Members can get details of other randomly selected members to send a postcard to, then receive cards from other random members. Official exchanges between the two members occur only once, but unofficial ongoing swaps between members are possible. As of November 2023, Postcrossing had over 800,000 members in 208 countries. By January 2023, 70 million registered postcards had been exchanged.