StarMail is the in-game email service, from which the player character Beatrix will receive information throughout the game.
From the game
Hi there, Beatrix! I heard you have some pretty cute slimes, especially puddle slimes! I suggest you make an entire area full of puddle slimes! sound crazy, right? well, I have one at my ranch! You can make a lot of new bucks from a puddle farm. Keep them busy with plenty of ducks! -A puddle slime lover
