No. They also offer you a free 30-day trial to utilize their traffic analysis tools. After 30 days you have to pay for the analysis service, but the counters are still free after the 30 days.
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 .