Take a look at this. Absolutely nothing wrong with being introverted - help them to be comfortable with it. Also, I think everyone feels socially awkward at some time or another. Just make sure they don't feel alone in it.
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 .