Choose the Content Approval Option in SharePoint 2010
Content Approval is approval-light; it’s a SharePoint 2010 publishing function that you turn on or off at the list or library level and it has just a handful of configuration settings. Content Approval — or moderation — doesn’t include item routing or notifications, and it doesn’t facilitate reviews and commenting.
What Content Approval does do is help to ensure that drafts and new uploaded content don’t get published to your list or library until someone with some authority says it’s okay, and the Content Approval process controls who can see those things in the meantime. Content Approval also can specify (in the case of documents) whether items must be checked out before they can be edited.
And Content Approval can hide draft documents from everyone except the item author and those users with Approve permissions on the list or library (contrast this with draft item security on libraries without Content Approval enabled in which you can limit views only to users with library-level Read permissions or users with library-level Edit permissions).
This is a subtle distinction, but specifying that only the item author and users with Approve permissions can view items means that the author can check in an item without exposing it to the view of other readers or editors until it’s formally published and approved.