What are the differences between the FIO Address and Public Key?

A FIO Address is a memorable "identifier" that eliminates the need to see, or even know of, blockchain public addresses. FIO Addresses are the entryway to the rest of the FIO Protocol, an entire layer of new usability features that makes your crypto better and easier to use.

If you accessed the FIO Address pre-sale site, you can bid on a custom domain, which gets assigned to your public key when you link your wallet. You can only link one wallet at a time since it's tied to your FIO public key derived from that wallet