This is an entry in our Disneyland 101 Glossary: Disneyland Resort definitions in under 101 words, from Mouse Brief.
Disney sells a vast variety of metal pins for collecting, trading or displaying. These small metal pins may depict popular Disney characters, attractions or locations in colorful enamel. They are sold at various price points. A popular pastime among some guests involves collecting these pins and trading them with other guests or cast members. Disney has developed particular policies and procedures around this hobby, and there are designated places around Disneyland Resort where collectors may display their pins for trading. Cast members are also sometimes given pins for trading with guests and will display them on boards or lanyards.