BigChampagne - Marketing research focused on file-sharing networks, with "TopSwaps" charts of most-popular musical tracks and artists.
Bitzi - Community-built media encyclopedia where file-sharing users identify and rate digital files, including images, music, movies, and software. Several P2P software provide an option to use this feature to check a file before downloading it.
Bluetack - A file sharing security solutions portal housing Protowall and Blocklist Manager.
File Share Freak - Provides general information, tips, and tutorials on file sharing.
FileSharingz.com - Provides news, tutorials, detailed guides for each network, client downloads and a community forum.
The Foundation for P2P Alternatives - Studies the impact of peer to peer technology and thought on society and aims to be a pluralist network to document, research, and promote peer to peer alternatives.
P2P Blog - Blog covering the business, technology and culture of peer to peer. By Janko Roettgers.
PP International - A collective for the Pirate Party movement around the world. Offers news and a common resource for international collaboration, and can provide help to form a local party in a given country.
P2Pnet - Covers news which are relevant to peer-to-peer file sharing.
Slyck - News site with regular articles and statistics on the state of major P2P networks.
Wikipedia: File Sharing - Encyclopedia article covering concepts and issues related to the practice of making files available for download over the Internet and smaller networks.
Zeropaid.com - File-sharing portal featuring news, content, downloads, interviews and reviews for P2P clients.