All content on a Drupal website is stored and treated as "nodes". A node is any posting, such as a page, poll, article, forum topic, or blog entry. Comments are not stored as nodes but are always tied to one. Treating all content as nodes allows the flexibility of creating new types of content. It also allows you to painlessly apply new features or changes to all content.
Behind the scenes, the Node module manages these nodes. This module is what lets you:
- List, sort through, and manage all the content on your site.
- Set defaults for how all posts are displayed.
- List and configure the "content types" for your site, and create new ones.
Offering "content types" is a way Drupal allows you to have different kinds of nodes for different purposes. For example, an "article" is one kind of content type, a "book page" another, and a "blog entry" yet another. You can also create new content types of your own.
The Node module manages the creation, editing, deletion, settings, and display of the main site content. Content items managed by the Node module are typically displayed as pages on your site, and include a title, some meta-data (author, creation time, content type, etc.), and optional fields containing text or other data. (Fields are managed by the Field module in Drupal 7.)