1) Anonymity network 
YaCy (pronounced `ya see`) is a free distributed search engine, built on principles of peer-to-peer (P2P) networks. Its core is a computer program written in Java distributed on several hundred computers, {As of|2006|9|lc=on}, so-called YaCy-peers. Each YaCy-peer independently crawls through the Internet, analyzes and indexes found web pages, an.....