Namecoin is an open source decentralized key/value registration and transfer
system based on Bitcoin technology (a decentralized cryptocurrency).

It allows you to:

    * Securely register and transfer arbitrary names (keys), no possible
      censorship!
    * Attach values (data) to the names (currently up to 520 bytes, will be
      extended)
    * Trade and transact namecoins, the digital currency NMC

To register a name, you must own some namecoins (NMC, the internal
cryptocurrency used by the software).

WWW: https://namecoin.org/