WordPress uses a concept of Roles, designed to give the blog owner the ability to control and assign what users can and cannot do in the blog.

WordPress has five pre-defined Roles: Administrator, Editor, Author, Contributor and Subscriber. Each Role is allowed to perform a set of tasks called Capabilities. There are many Capabilities including publish_posts, moderate_comments, and edit_users. The default Capabilities are pre-assigned to each Role.

The summary is given here :

• Administrator –  has access to all the administration features
• Editor -can publish and manage posts and pages as well as manage other users’ posts, etc.
• Author – can publish and manage his own posts
• Contributor – can write and manage his posts without uploading file,  but not publish them
• Subscriber – can only read posts and  manage his profile