If you are having a problem getting/staying connected (logged on) to the main site, it could be a cookie problem. Here's a link to FAQ instruction on fix.
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 .