Overnet

Overnet is a File Sharing program.
Overnet does not have servers at all. It is a complete Peer-2-Peer network where all clients connect directly to each other.

Just as the eD2k network, Overnet knows when files are different even if they have the same file size and name, ensuring that unique files are properly presented and that when several identical files are found it can download from those independent sources at the same time.
This also allows you to create links to the files.

However, Overnet is a closed protocol. This means that it's specifications are unknown and it's designers aren't willing to show them to the public.