My son played against him for years. On his Twitter account was written "...rivals, but not enemies." An enormous talent gone much too soon, such a shame.
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 .