Blocks is a term for the rectangles of information you can use throughout the portal. For the sake of simplicity the page has been divided into the "panels", which when combined can mimic many common page layouts. These blocks can contain regular html, php code or special written functions that collect specific types of information. You can show them according to which permissions the visitor has, and even show them just in certain sections. You will come to love playing with them.
Go to the TinyPortal 'forum page' to see several Block types in action.