We characterize publication and retrieval of documents in peer-to-peer file-sharing systems and contrast them with query answering in peer-to-peer database systems. We show that the simplicity of file-sharing systems avoids many problems faced by P2P database systems. We propose a simple and open meta-model for documents and meta-data, for the purpose of expressing arbitrary relations between documents, peers, and file-sharing communities. Such relations in effect define a semantic enhancement to P2P file-sharing systems and enable the distributed emergence of knowledge. We illustrate our study with the description of our system, which distributes queries only to relevant peers, and can translate queries across different meta-data schemas.