Jane,
A candy swap also known as a charm swap, is a swap of a posted amount of fabric squares cut to specific size. A host receives the agreed upon amount to swap from each swapper and distributes to all swappers. Mailing deadlines are involved regarding mail to host & host to swappers. A candy swap is a way to build a greater number of squares to complete quilting projects. There is positive feedback to be earned upon completion of the swap. Rules for the swap are posted on the thread for each swap so there isn't a lot of guess work involved. It's a lot of fun.
Another type of swap is a "fat quarter" swap (18x20 cut fabric). This type of swap helps quilters complete larger scaled projects.
I am waiting for Quilting Board leadership approval to host a 2.5" charm swap & will post a new thread to sign up when we get approval. We hope you will join in the fun! If you need further information, please send me a Private Message (PM me)!
djmat