At first blush, Trodo looks like any other sell-your-stuff Web site. The difference on Trodo is that you don't get money for your stuff; you get more stuff. For example, when someone requests a CD you've listed, you ship it to them, and when they receive it, you get a CD credit that lets you request a CD from someone else. At this writing, Trodo also lets you trade books, videos, video games, and (just added recently) clothes.