Topic: Web resources
So much talk about Artist Trading Cards (ATCs) even though they've been around for years!
These are mini-works of art, usually made individually, that always have the same measurements and are always traded - never sold. There are whole groups of traders out there in cyberspace and many sites that will get you started. The one I find most comprehensive is http://www.cedarseed.com/air/atc.html
I've noted a few books out on the topic, as well, such as:
Artist Trading Card Workshop: Create, Collect, Swap by Bernie Berlin
1,000 Artist Trading Cards: Innovative and Inspired Mixed Media ATCs by Patricia Bolton