This is known as a *moderated* discussion board. It means the people here at AndyKimMusic.com care enough about it to assign people to watch over it and keep it a nice place to hang out.
In order to make that happen, we have to maintain some degree of control over the Board. By asking people to register, we are able to ban those users that refuse to respect other people. It's as simple as that.
We respect your privacy. When you register, we require only your real e-mail address for security purposes. (Your user name does not have to be your real name.) Any other information you volunteer is completely up to you. And under no circumstances will we share or distribute this information to anyone else.