Note: This page is about the free Members plugin which is a User Roles and Capabilities editor. If you’re looking for a plugin that will allow you more control over restricting your content with the added ability to charge your member’s for access, you should consider MemberPress.

Members is a WordPress plugin that extends your control over your blog. It’s a user, role, and capability editor plugin that was created to make WordPress a more powerful CMS.
It puts you in control of permissions on your site by providing a user interface (UI) for WordPress’ powerful role and capabilities system. Traditionally, this interface is only available to developers who can code by hand.
Features
Role Editor: Edit, create, and delete roles as well as capabilities for these roles
Multiple User Roles: Give one, two, or even more roles to any user
Explicitly Deny Capabilities: Deny specific capabilities to user roles
Clone Roles: Build a new role by cloning an existing role
Content Permissions: Control which users (by role) have access to post content
Shortcodes: Control who has access to content
Widgets: Login form widget and users widget to show in your theme’s sidebars
Private Site: Make your site and its feed completely private if you desire
Plugin Integration: Members is highly recommended by other WordPress developers. Many existing plugins integrate their custom roles and capabilities directly into it.