ETHMail is an email hosting service. It providers mailboxes for all people who have Ethereum wallet.
Because we need a way to leave messages for people who we don’t know anything about except for their Ethereum address.
And it needs to be simple.
It depends: Do you want to send a message to someone or check if anyone left a message for you?
You can just go to your gmail/yahoo/hotmail/etc account and just send normal email to
[ETH address]@ethmail.cc (example
The easiest way is to login using your Ethereum wallet at web.ethmail.cc