the difference between a page node and a story node?

Here is the official party line, followed by my - hopefully less ambiguous - explanation.

Site page
Site pages are static pages which are typically (but not required to be) linked into the main navigation bar. One special thing about them is that they can contain customized PHP code in order to make their content dynamic.

Story Page
Story pages are the generic page type that most content management systems have. Stories are generally used for information which is only relevant for a period of time (eg. news stories) and is expected to expire off of the page.

Book Page
Book pages are designed to be part of a collaborative book. An example of a collaborative book is the Drupal developer documentation. Originally only book pages could be a part of a book but these days all node types can be part of a book. Really the only special part about book pages these days is that like static pages they can contain PHP code.

Story, Page, and (for what it's worth) Book Page (or as the documentation is now referring to them Site page, Story page, and Book page) are really all the exact same thing. Period. There is absolutely no difference between them. From what I can tell, at one point, way back - 2003ish there were some differences, this is no longer the case.

Unlike the documentation leads you to believe...

• None of them are added to the Navigation by default, but any of them can be added.
• Any of them are capable of being treated as "Static" if that's what you want. But in Drupal there is really no such thing as static so you might as well not even think that way.
• All are are completely capable of executing PHP if the user's role allows it.
• All can be pulled into summary pages (taxonomy pages)
• All can be moderated and/or put into the approval que
• Any of them can be made part of a book as long as the book module is enabled.

It is extremely confusing because the existence of these different node types implies that there is a functional difference between them — there is not.

Any difference is entirely in how you choose to implement them. For instance, I use 'page' nodes for permanent pages on the site, many of which have complicated html/javascript/php etc. I set the priveleges so that only an users with a role of admin(which I created) can create/edit/delete pages.

I use stories for eveything else. So in reality the only reason *I* am using the 'page' nodes at all, is so that I can excercise some administrative permissions based on node type (that, and I set the defaults for pages not to have comments, I hide the author info, links, terms, etc. But I could have just as easily reversed my use of these nodes and used stories where I used pages and vice versa. There doesn't have to be a difference at all.