saminwy,
When you log on using your name and password, then the next page that comes up is the MAIN FORUM PAGE. Right at the top left edge you will see a small "red" flag showing you that you have Inbox Mail. Now just look over to the top right and look for the word "INBOX Mail", click on that and that is where you will find a message that someone has sent you. Only you and the person who sends it can view it, and you can reply back this same way.
To send someone a personal message, look right nest to their name say for the example: Kilowatt you will see some icons and the first one is like two envelopes, this is for a person e-mail address. The next icon looks like a single envelope, this is for the MM.com Inbox personal mail. The icon showing a head profile is what the person has entered when he became registered.
Not everyone is telling you their name some a made up and some are not even enabled.
I will send you an Inbox mail so you can see what I am talking about.
Brian