BBCode is a variation on the HTML tags you may already be familiar with. Basically, it allows you to add functionality or style to your message that would normally require HTML. You can use BBCode even if HTML is not enabled for the forum you are using. You may want to use BBCode as opposed to HTML, even if HTML is enabled for your forum, because there is less coding required and it is safer to use (incorrect coding syntax will not lead to as many problems).