Freenet

The freenet project has some specific goals:
- To allow people to distribute material anonymously.
- To allow people to retrieve material anonymously.
- To make the removal of material almost insuperably difficult.
- To operate without central control.
The search protocol works like gnutella except that:
- Nodes keep a copy of the data. They work as caches. The most popular data will be replicated many times.
- Searches are done depth-first, instead of breadth-first. That is, the request is sent to only one other node at a time.
- It uses its own port.
- The documents are given a unique identifier. The query strings are hashed. Therefore, you need to specify the exact ID of the document you want. They would need to be published in a website.
In general, it requires a lot of cooperation from the nodes, like blindly keeping copies of any material.