[edited: stay on topic. If you want to complain do it in a thread about complaints or in the everything else forum. Dont reply to this thread or you'll get a 1 week vacaction from the boards.]
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 .