Perfect Dark is an anonymous peer to peer network which aims to become the #1 in Japan. You have to share at least 40 Gigabyte of your hard drive which is used for the networks exceptional storage system which works like a global RAID array. Everything a user uploads will be stored in tiny encrypted parts over the space of thousands of users. But it’s more than just anonymous file sharing, you can also create boards and post on the ones of other users. Since 100MBit/s is widely the normal way to surf the net in Japan, Perfect Dark demands at least 100KByte/s.
Download link: Perfect Dark 1.10 (latest)
After running the binary it installs itself to the current directory and asks you for a few settings. You have to open a port and fill in an encoded address of another node in order to get it working.