Here's How Facebook Nanny Works-
1. Whenever you go on Facebook, you only get to spend one minute on the site for each notification that you have.
2. After that time, your access to Facebook is removed until you receive another notification.
3. You ARE allowed to access messages and your profile at any time, so you can still make posts and chat with your friends.
Facebook Nanny doesn’t prevent Facebook tabs from being opened, but the page is grayed out, and you cannot interact with it at all. Since it’s still open, you should see new notifications in the tab or in the few seconds before the page is grayed out. For each notification you get, you can spend 1 minute on Facebook and navigate to any page of your choice. Your profile page, messages, and thus, chat will still be unbarred at all times.
Facebook Nanny is a reasonable approach to keeping you productive rather than completely locking the Facebook, this extension still allows you to keep up with essential Facebook activity.
Extension Link - Facebook Nanny