Using your Mail firstname.lastname@example.org
The inbox shows messages you have received from other people. You can View or Delete each message. When viewing a message, you can press the player's profile icon to see their Profile or use the text box at the bottom and the Post button to write back.
The feedback section lets you write a message to ask for help, report other players, give suggestions or just tell us what you think of the game. These messages go directly to admins (helpers and moderators won't see them). The admins will try to get back to you as soon as possible.
Pressing e-mail lets you write a message to another player. Just put their id in the receiver box if you know it, or press Friends and Choose someone on your friends list to message, then write your message below and Send.