The distributed data store of Freenet (with same principles as a blockchain) is used by many third-party programs and plugins to provide microblogging and media sharing, anonymous and decentralised version tracking, blogging, a generic web of trust for decentralized spam resistance, Shoeshop for using Freenet over Sneakernet, and many more.
The origin of Freenet can be traced to Ian Clarke's student project at the University of Edinburgh, which he completed as a graduation requirement in the summer of 1999. Ian Clarke's resulting unpublished report "A distributed decentralized information storage and retrieval system" (1999) provided foundation for the seminal paper written in collaboration with other researchers, "Freenet: A Distributed Anonymous Information Storage and Retrieval System" (2001). According to CiteSeer, it became one of the most frequently cited computer science articles in 2002.
Researchers suggested that Freenet can provide anonymity on the Internet by storing small encrypted snippets of content distributed on the computers of its users and connecting only through intermediate computers which pass on requests for content and sending them back without knowing the contents of the full file, similar to how routers on the Internet route packets without knowing anything about files—except Freenet has caching, a layer of strong encryption, and no reliance on centralized structures. This allows users to publish anonymously or retrieve various kinds of information.:152
Freenet has been under continuous development since 2000.
Freenet 0.7, released on 8 May 2008, is a major re-write incorporating a number of fundamental changes. The most fundamental change is support for darknet operation. Version 0.7 offered two modes of operation: a mode in which it connects only to friends, and an opennet-mode in which it connects to any other Freenet user. Both modes can be run simultaneously. When a user switches to pure darknet operation, Freenet becomes very difficult to detect from the outside. The transport layer created for the darknet mode allows communication over restricted routes as commonly found in mesh networks, as long as these connections follow a small-world structure.:815–816 Other modifications include switching from TCP to UDP, which allows UDP hole punching along with faster transmission of messages between peers in the network.