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 ca

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.