Both son's use it. If you are using it, and have access to the data, the definitions of those scores are in the report. Here's a screenshot of the definitions.
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 .