| "A website is not a magazine, though it might have magazine-like articles. A website is not an application, although you might use it to purchase products or interact with other people. A website is not a database, although it might be driven by one."
This feels overwrought. A website is a collection of documents (webpages). That's it. A document is just a vehicle to store and/or transmit information. They can be made to be pretty and engaging to make that information easier to consume.
If a website is only a collection of web pages then you cannot have Amazon, hotels.com or any other site where the user pays money and receives something physical as a purchase.
So the document metaphor is too simple as it only describes what happends at the html/css level but not how the user interacts with the site and the purchases that result from this interaction.
But it's not a metaphor, it's literally how browsers as clients relate to webpages. Your browser is essentially just a very specialized document viewer. It's capability to enable those documents to dynamically incorporate other internet resources (like Amazon or Hotels.com do) even has "document" in it's name: Document Object Model. Sure, those other resources can be a component of the site, but they're mostly useless without that document providing interaction with them.
This feels overwrought. A website is a collection of documents (webpages). That's it. A document is just a vehicle to store and/or transmit information. They can be made to be pretty and engaging to make that information easier to consume.