Postcrossing is an online project that allows its members to send and receive real postcards from all over the world. The project's tag line is "send a postcard and receive a postcard back from a random person somewhere in the world!”. Its members, also known as Postcrossers, send postcards to other members and receive postcards back from other random Postcrossers. Where the postcards come from is always a surprise.
Postcrossing is the union of the words "postcard" and "crossing" and its origin "is loosely-based on the Bookcrossing site". However, the "crossing" or exchange of postcards works in a different way. A member sends a postcard to another Postcrosser and receives a postcard back from a random Postcrosser. Exchanges between the same two members only occur once; although direct swaps between members happen, they are not part of the official happenings on the site. The project is completely free and anyone with an address can create an account. However, the postcards themselves and postage fees to mail them are the responsibility of each user.
As of September 2011, Postcrossing had over 251,000 members in 198 different countries who had exchanged over 8.4 million postcards that have traveled over 45.8 billion kilometers.
The highest concentration of Postcrossing members reside in the United States, China, Russia, Taiwan, Germany, the Netherlands and Finland. Globally, most Postcrossers reside in North America, Europe, and East Asia
The main idea is that if a member sends a postcard he or she will receive at least one back from a random Postcrosser somewhere in the world.
The first step is to request to send a postcard. The website will display (and send the member an e-mail) the address of another Postcrosser and a Postcard ID. The Postcard ID uniquely identifies that postcard in the system. The member then mails a postcard to that Postcrosser and writes the Postcard ID on it. The Postcrosser receives the postcard and registers it using the Postcard ID that is on the postcard. At this point, the member is eligible to receive a postcard from another Postcrosser. Where that postcard comes from is a surprise!
Initially each member can have up to 5 postcards traveling at any single time. Every time one of the sent postcards is registered, that Postcrosser can request another address. The number of postcards allowed to travel at any single time goes up the more postcards a member sends.
The Postcrossing system allows for the same two members to exchange postcards only once. By default, members will exchange postcards with countries other than their own; however, the users can decide to exchange postcards with other users in his or her own country.
A small percentage of mailed postcards get lost during their travels; others may arrive with the Postcard ID unreadable and are difficult to register. There are also members who become inactive while postcards are on the way to them. The system behind the website accounts for all these factors and compensates active members by attempting to reduce the difference between the number of sent and received postcards of each member.
Learn more about it on the official website!