I've only found full screen mode when in "Show" mode from the menu on the right hand of the screen (If it's closed away, there's a small arrow to expand it).
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .