How do you stop a liar?

Someone asked me tonight, "How do you stop a liar?"  So, I googled the question.  Isn't the internet fun?

I found these comments interesting.  There is a difference between Pathological and Chronic liars.  I landed on the pathological in regards to this question as well as the quote just below.

"Liars lie because they can lie. Over time they become experts in lying. Their success today depend on their ability to lie. 
They have become dependent on this habit. Lying gives them a feeling of control in a situation they cannot control. Notice the word "feel". In other words, they assume they cannot control the situation if they don't lie." www.searchwarp.com/swa53901.htm

"Pathological Liar

A pathological liar is usually defined as someone who lies incessantly to get their way and does so with little concern for others. Pathological lying is often viewed as coping mechanism developed in early childhood and it is often associated with some other type of mental health disorder. A pathological liar is often goal-oriented (i.e., lying is focused - it is done to get one's way). Pathological liars have little regard or respect for the rights and feelings of others. A pathological liar often comes across as being manipulative, cunning and self-centered."  http://tiny.cc/ZyYJ8

So, the question was "How do you stop a liar?"  I found two answers.   1)  Call them on the lie.  But you know they will just seek a new audience.

2)  Stop listening to them.  And that one seems the best.  Notice in both quotes above that the goal is to obtain an outcome - control a situation.  There is a focus and a desire to achieve a specific thing - a need to control a specific situation.  Refusing to even listen to the lie gives the liar no power - no control.

A friend sent me a book recently, "The Truth about Lying".  It covers the full spectrum from white lies to how we may make it difficult for others to tell us the truth to those who make lying a way of life.

We all mislead people sometimes.  Telling someone we like their new haircut when we really don't or that they look thinner than we really think or that we like their outfit when we really don't.  Or we don't tell them about our own shortcomings in a job interview.

So what is the cutoff point with lying or "misleading"?  And when do you determine that a person is just simply a liar and should no longer be given an audience?

Perhaps it is in the fallout of the lie.  Who is going to be hurt?  Who is going to benefit?  How great is that benefit?  How large is the fallout?   And finally, how often is what this person says a LIE?