Just what it says on the tin.
What do you have of economic value that you can offer to other Christians? This can be in exchange for something that they have; but more generally, be thinking about what you can offer for free, trusting that God will provide for your needs through the same system.
You can start this simply, today, by offering something to someone you know.
Long-term, wouldn't it be great if our clothes, food, shelter, water, electricity, etc were provided by people we knew and loved? Or people who were only one or two degrees of separation from us? That's what our interlocking system of mutual interest groups would do.
My dream for this section of the website is that it would turn into the Currency-less Craiglist for Christians. I'm still thinking about the best way to go about that.