simplified, data can be attached to a TX(transaction) not an address itself.  that data can be nearly anything and if used right, with a well formed smart contract, it can be the future of bitcoin, and the economy.  

Think about this, you order a pizza online using Bitcoin, your address, the order and all that info is embedded in the transaction itself.  using the data as meta data or json values, the computer at the pizza place can easily parse the data and without a single person touching it, send the order to the kitchen computer, the address to the delivery guys GPS in his smart phone and even send a portion of the amount paid directly to the delivery guys Bitcoin address as a tip.  there is not room for a huge amount of data, but there is plenty of room for a link to a json on a server