Blockstack.org has defined a nice decentralized profile system. It defines a zone file to look up the profile data. It is defined in their white paper and on some articles. Look for Blockchain Naming System (BNS)

The user can choose where the data is stored, i.e. it is decentralized, better protected against single point of failure. What happens if the eostitan servers fail? The zone file is small and is store on chain.