This is fucking incredible.
Peer-to-peer describes a way of directly networking computers together without a central server. It's how many filesharing systems work.
There's some fascinating exploratory, theoretical work going on with this stuff these days, much of it assembled or developed by Michael Bauwens at the P2P Foundation. I doubt it was deliberate on the part of programmers who began this field, but this embodies the core of anarchist economic principles magnificently- decentralized groups of producers and distributors working through free association. This has always been possible, and indeed has always been a part of economic systems in the real world outside economic ideology. (See for instance the historical work associated with the flexible specialization school of development economics.) But thanks to the most powerful communications system in world history, it becomes that much easier. People can easily and efficiently act in swarms, or more importantly perhaps, share resources immediately and casually. So we're seeing the development of non-digital systems that are essentially peer-to-peer networks- dynamic ridesharing, peer-to-peer urban farms, networked microfinancing, decentralized green energy production, maybe even peer-to-peer desktop fabrication. The possibilities are fucking limitless, so check this out, see what makes sense, what you can use and if you can find inspiration from any of this.