By default, for reasons of privacy, your email address isn't visible to others on the bulletin board (i.e., they can't send you email since they don't know your address). However, email is a convenient and flexible method of communication, so if you change the Show my email address/name setting in your profile appropriately, others will be able to send you email. Similarly, if you want to send someone else email, check to see if they've made their address visible by visiting the member list, or by clicking on the link under their Username if you're viewing one of their posts. Note that you don't need to change the email setting in your profile to send email, just to receive unsolicited email from others.
Private Messaging (or PM for short) offers greater privacy than email. Since the bulletin board itself handles communication in both directions, nothing personal about you (other than your username and what you write) is made visible to your correspondent, and vice versa. You must be a registered user, currently logged in to the bulletin board, before you can use PM. Here's how it works:
By default, if someone sends you a PM, you are sent an email alerting you to the fact. If you'd rather not receive email notifications, edit your profile, and uncheck Send email for a new Private Message. Also, any time you're logged in to the bulletin board and you have one of more unread PMs in your inbox, the icon will appear next to the Messages link in the gray menubar. Click on the link to retrieve your message(s). The interface is simple. You have two folders: an inbox and a sentbox. Messages sent to you by someone else appear in your inbox, and copies of messages that you send to others are saved in your sentbox. To read a message, click on the subject line. To delete a message, read it and click the delete button. To switch between folders, click on the relevant link at the bottom right of the window.
To reply to a message from someone else, read it, then click on the reply link below the message. A copy of the message you're replying to will be included in your new message. This helps your correspondent remember what the conversation is about. You can type your message before or after the included original message, the choice is yours. If you really don't want the original message to be included, just delete everything in the edit box before typing your message. Separate help on editing a message is available.
You can send someone else a new PM in one of several ways. Usually you'll be reading a post and want to communicate with the author. In that case, while reading the post, click on the author's username to bring up their profile, then click on the icon to send them your message. Alternatively, you can visit the member list and click on the icon alongside your desired correspondent's username. Alternatively, you could click on the Messages link in the gray menubar and click on the New Message symbol.
Bulletin Board Help Page