This might be old school for many who are already familiar with WordPress, however I still get many questions about user roles settings in WP from those who are not yet quite familiar. So, briefly here goes.
WordPress allows users to register for various roles regarding the blog content access.
An Administrator has all the levels of access to all the functions within the blog. This would include the blog general settings, the appearance settings, user registration and access and all the configuration settings of the entire blog. Simply speeking, the administrator has overall superaccess to everything. Although WordPress is known to be user friendly, it is best to leave the administrator role to those who are sound and familiar with the overall blog configuration settings.
One level below the Administrator is the Editor. Now the editor does not have access to control the settings for the blog configurations but has access to managing the contents of the blog trhough postings, pages, links & related matters regarding content editing.
An Author has access to creating content in the blog for his or her posts and pages only and like the Editor, the Author does not have any access to the blog configuration settings or whatsoever except those regarding his or her own posts, including its comments.
A Contributor can write a post to a blog, however he or she can not publish them. The posts written by a contributor will have to be approved by either users higher in the hierarchy such as an Author, Editor or an Administrator.
The last user level at the lowest hierarchy is the Subscriber. The Subscriber can submit a comment to a post or page when allowed by the post author. Depending on the blog configuration setting by the administrator, comments can either be automatically published or be held for moderation by an administrator, editor or the respective author.
So, there your go and so you know.