Accdng to Frankfurt, how are the bull-shitter and the liar similar and different. 

 bullshit is spoken without any concern for the truth. It can be true or false, but the speaker does not really care. they both seek to deceive us about themselves. The liar seeks to make us believe that she believes her lie (that is, she knows some claim P is false, asserts P, and in so doing of course asserts that she believes P), and the bullshitter seeks to make us believe that she is saying something that she supposes is true (she makes claims like P in her bullshit, and we so in a way asserts P and asserts that she believes P, but in fact she does not care if P is true or not).But the liar believes she knows the truth, and then asserts something inconsistent with it. The bullshitter need not know the truth. She need not care.

Accdng to Frankfurt, how are bull-"sessioners" and bull-shitters similar and different. 

 A bull session appears to be a harmless discussion where people without much seriousness discuss some issues. 

Accdng to Frankfurt, why is the connection btw bullshitting and bluffing closer than that between bullshitting and lying? 
 Bullshit may also be like bluffing and phoniness, in this regard. What is objectionable to phony things is how they were made. The bullshitter is not concerned, in producing his or her product, with ensuring it is made in the right way -- that is, made with attention to facts.
One might prefer bullshit to lying becuase it is more accepted -- there is no clear culpability.
What particular response to the cultural proliferation of BS does Frankfurt regard as itself bullshit, and why? 
Bullshit is inevitable when someone speaks of something about which they are ignorant. Perhaps there are many such occasions arising from, for example, the demand on public figures to speak on everything, or from the notion had by some people that we should have opinions on everything.
Bullshit might be a product of a skepticism or relativism that leads people to think that sincerity is more important than any rigorous standards of reasoning.
In the Amoralist, Williams argues that to be consistent, the amoralist must do or avoid what? 

 amoralist must avoid consistent resentment and disapproval of people treating him in the same manner he treats them.  Not liking such treatment, and even fighting back, is acceptable as those reactions do not necessitate moral considerations, but resentment and disapproval are attitudes that generally result from moral considerations, and the more consistent the attitudes are the more likely it is that they stem from some moral precept.
The amoralist must avoid considering himself, or anyone else, as courageous, splendid, or excellent

The difference between the Amoralist and the Immoralist is what?

The difference between an amoralist and immoralist lies not in their respective actions but rather in their beliefs about the nature of morality. The immoralist is recognized by his (immoral) actions, but is conceivable that the behavior of the amoralist confirms to the accepted moral standards in a given society, and what makes him an amoral person is the lack of certain essential beliefs about moral principle and moral values, which presumably, the immoralist still retains despite his behavioral failures, 
The amoralist all moral goodness and moral obligations are "of the relative kind", nothing is "good in itself", and no person for him has "intrinsic worth"
 person who is amoral does not understand the difference between right and wrong, so it means that person is neither moral nor immoral.  
A person who is immoral understands the difference but does wrong anyway.  
Amoral means \'not concerned with morality\' while immoral means \'not conforming to moral standards\' or \'evil\'.

Accdng to Williams, the amoralist is potentially unrecognizably human insofar as what? 

 The fundamental difference between the psychopath and the amoralist is the ability and desire to care for somebody other than one\'s self. Even if such a care is wholly self-interested and contingent on how one is feeling on a particular day, this fleeting feeling distinguishes the amoralist from the psychopath (Williams 8). And for this reason, Williams dismisses the psychopath as being a possible alternative to living a moral life. The psychopath merely "appalls" us, and he leads us to seek to understand why (Williams 9).