How/What are ATC's used for?
ATC's are a collectors treasures. They are swapped by artists through online trades or organized trading sessions around the world. They are also rather addictive, because it's almost impossible to make just one. ATC's are just for the fun of it, for gathering new ideas, for collection purposes, for meeting friends and fellow artists, for all types of things. ATCs are ideal for those who like small, quick projects, for testing new techniques, trying out new rubber stamps, or just playing. Many paper crafters swap these through online groups. I enjoy making them when I just want to play with an idea or try color combinations I'm considering for another project.

ATC Tips:
-- Dimensional embellishments are acceptable, but remember that your finished card must fit into a standard trading card sleeve.
-- Making cards larger than the established dimensions is poor form. This is not allowed in many trading card groups and if it is allowed, it will usually insure your cards are less desirable when swapping.
-- The back of your cards should contain your name, any contact information you wish to provide, the date, your signature, and the number or series of the card. Some artists start numbering their cards with number 1, and just keep going. Others will do series numbering, such as 1 of 7 or 1/7. How you number is totally up to you.
-- When choosing stamps and collage materials, remember to scale everything down a little. Be sure to save those tiniest of items for your ATCs!