They are basically like business cards, but smaller, and more personal, with an online profile attached to them. See their web site for more detailed information. Not that there is much - they really need to work at explaining the concept better.
Insanely long shipping time (over two weeks) but they are very nice. They feel almost like they are made of plastic rather than paper, and are machine washable. They come in a plastic, not paper box, which is also very nice. I cannot wait to try them out on people!