As we get closer to the release of the new Card Mode interface, we will be testing it here on this site for awhile, starting later today. Thus, you'll be getting a sneak peak at some of the functionality.
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 .