What is the difference between addresses that start with "R" and addresses that start with "z"?

Komodo Platform is built upon and extends the Bitcoin protocol. It also provides Smartchains access to zero knowledge technology. 

Addresses which start with "R" behave exactly like Bitcoin's, including their globally public properties and we refer to these as "transparent addresses". 

Addresses which start with "z" include the privacy enhancements provided by zero-knowledge proofs (pioneered by Zcash) and we refer to these as "shielded addresses".

While z-addresses are disabled on the KMD chain,  the Pirate chain allows only z-addresses for users and some of the other Smartchains have z-addresses enabled.