If you have been using Safari, grab the latest version of Firefox and see how that goes. That WYSIWYG text editor and Safari have yet to come to terms with one another.
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 .