I noticed it yesterday as well. Looks great. One minute I was looking at the old format, and then the next click of a button and it was the new format... had to do a double take for a minute there. lol.
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 .