OK., we're here very much at the first stage of site development. Let's see where this all leads. Although I have installed and played with Drupal several times prior to this current install, this may the first time so far that I feel like I am getting a slight handle on the various means, methods and other madness that is Drupal.
The Drupal System or Framework as I sometimes hear lately, is a VAST conglomeration of tehcno-stuff (highly technical term here) designed to display web content via someone's browser and uses a database within which to store all of this content. This differs considerably from the "old style" of static HTML only web site from the days of yore.
The traditional (before CMS) type of web site used static web or HTML pages for each page of content that a web site would display and every new piece of content then required that the web site builder create a new page of the web site for that new content. A web site could grow to be hundreds of pages (and more) very easily with this type of system.
The CMS method instead places all of the content into a database and the front end, so to speak, of the web site then actually generates the HTML code for each page as the internet user requests the particular content or pages via their web browser and then the content gets rendered dynamically to the browser.
This concept allows relatively HUGE amounts of data, content and anything else that can be rendered over the internet to be cataloged, displayed and accessed via the CMS or Content Management System. Drupal was designed to take advantage of this and even goes beyond in many respects by adding a customizable modularity to the framework.
As such, Drupal can be designed to handle almost any task imaginable by the designer developer of a web site, whether that is a huge art / music collective or library, an online storefront catalog of products and items for sale, or a social networking site with thousands of registered users that create their own content.