I'm using MyEtherWallet to register/map the EOS key. The steps suggests to use
register() function, however in another tutorial I've seen it's using
claimAll() function. So, I'd like to know the difference. For example, do I need to claim all after I register?
Claiming is used to claim your EOS tokens that you bought on the official ICO. Every time you buy tokens you have to claim again.
Registering is used to register an Ethereum address that holds EOS ERC-20 tokens you bought on an exchange (or received from another person). You only need to claim an address once, when you add more tokens to that address all of them will end up properly in the snapshot for the main net.