Movable Type 4 gives us a rich vocabulary of information elements from which to construct small business web sites. As I write this the ultimate irony is that I am using version 3.xx to tell my clients about a feature of 4.x; I really must get this blog cut over to the new version.
An Entry in MT is sometime called a post. This is because MT was originally weblogging (blogging) software. Blog posts, or entries are sequential over time. The last one you write is more current than the previous. Over time they will both become history, archived as it were, but no longer front page news, so to speak. For many business web sites, blog entries serve the same function as news.
Entries can be organized into Categories, and they are placed in chronological Archives by default.
A Page in MT has only existed as a separate informational entity since the latest version, 4.x. Pages are similar in their scope and general information make-up (such as title, content, keywords field, etc.) to a news item but they are more timeless. The information they contain is very slowly changing if at all.
Pages can be organized into Folders.
Both Entries and Pages can be indexed using logical devices called Tags.