In your control panel, go to Chat>>Chat Rooms. Click on “Edit”
for the Chat Room for which you wish to change permissions. Click on
the Permissions tab. Set the appropriate permissions and click on “Save Chat
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 .