namecoin

 Namecoin  is a bitcoin fork which was created to handle, buy and manage .bit decentralized domains.

Pros:
 * decentralized
 * anonymous

Cons:
 * requires mining or buying namecoins
 * requires running a daemon to maintain the infrastructure
 * See

Issues
As of 2015-08, one person controls up to 75% of the compute power on Namecoin, meaning they can effectively control the blockchain.