A Messenger Application in which you can write to any Ethereum Address. Check out the Prototype of the Dapp on https://donno1994.github.io/Ethereum-Messenger
The Smart Contract Code is available on https://ropsten.etherscan.io/address/0x9ce05d558d6da9e6af44cfe788e2e54f8845802a
The Mainnet Contract will follow after successful implementation of smaller features.