It lets you restict site contributors' access to your web site by assigning each user a role:
Can access all areas of the Web site and can perform all tasks.
Can create new channels, layout all channels, and publish content.
Can create, edit, and approve content. This option is available on sites with no workflow.
Can create new content, edit their own content, and edit content that others have written if collaboration is enabled.
Can edit existing content, but cannot create new content.
Can approve content for publishing.
Can publish content items on the channels that you select. Layout publishers cannot create channels.
As a piece of content moves through each stage of the workflow process, the approval state is changed by someone in the appropriate role and the next person in the workflow is notified that they have content waiting for their approval.
Site administrators can customize their Workflow e-mail settings on the User Profile page. For more information, see Selecting Your Workflow Options.