what the website is about. So I go up a few folders manually... eg. I read
www.example.com/articles/internet/whyinternetisgood.html, then I manually enter the following into the URL: www.example.com/articles/ in order to see the index page containing all the articles.
This reflects the basic function of HTML/HTTP. Obviously Drupal doesn’t
Unofrtunately, you're very confused. This is not a basic function of HTML and HTTP but, rather, a side-effect of how the Apache webserver handles filesystem requests. In short: if the requested destination maps to a directory, then *Apache* (the webserver, not your browser, not the website software) will append a trailing slash - to indicate that this is a directory.
In a traditional Drupal example:
http://www.example.com/node/123 http://www.example.com/node
Neither of those Drupal URLs map to any literal file or directory on the file system Your base assumption - that you can then "go up a few folders" is inherently inaccurate, because *there are no folders*.
Take a look, for example, at:
http://www.disobey.com/detergent
This is a literal directory on my filesystem. If you attempt to go to that URL, you will see that Apache (the webserver) will issue an immediate and barely perceptible redirect which will send your browser to the URL with a trailing slash instead. Apache will *only* ever do this for directories. It's not going to do this for URLs served from a website's content management system, such as example.com/node above.
This even works for the base URL:
Notice there's no trailing slash - but, if you enter just the above into a browser, you'll see that Apache does the same barely perceptible redirect and you'll reach http://www.disobey.com/. One could almost infer that you can save scant ten thousandths of a second if you always append literal directories with a trailing slash - if you don't, Apache will just have to do it for you anyways (note that I've been following this practice forever - see my signature for instance).
As Michelle followed up, though, Drupal, the website software, will gladly accept a trailing slash *if the requested destination has content to serve*. Both of these URLs work:
http://www.disobey.com/node http://www.disobey.com/node/
Drupal is making them work because it knows that "node" is a valid destination inside the software. Compare, on the other hand:
http://www.disobey.com/taxonomy/term/18 http://www.disobey.com/taxonomy/term/18/
Both of those URLs work, but not this one:
http://www.disobey.com/taxonomy/term http://www.disobey.com/taxonomy/term/
Because there's nothing inside Drupal that exists at that destination (thus, it gives the standard "Page not found" error). You would certainly, however, be able to define your own node, and then alias both of the above URLs, if you so chose.
Your biggest problem is, however:
* You've misunderstood that path components of a URL directly map to a filesystem's directory/file structure; they don't.
* You've misunderstood that *every* literal directory/file structure allows you to browse up the hierarchy by just removing parts of the path. Compare, for example:
http://www.disobey.com/misc/druplicon.png http://www.disobey.com/misc/
These are literal files and directories, but one can't browse the /misc/ directory (in this case, because it's been denied, but whether Apache's DirectoryIndex is properly configured is also another measure of success).
* You've misunderstood that Drupal (or any website software) can't replicate this functionality; it can.