Chatting in Sociotown is easy to understand. To communicate to other players, you just have to start typing and a bubble on the lower left hand side will appear, showing you what you have typed.
You've Got Mail:
To check your mail, click on the Mail icon on the top left corner of the gamescreen. That will take you to your main Mail screen, showing your "Pigeon Post" capacity, your mail, the sender, and the trash.