I'm fairly certain that it has a VS detector and that is scripted to respond to VS with questions like 'how do those compare' ... just like it has a 'EQUALS' detector to determine if you are doing deduction ... or a swear word detector to determine if you are swearing at it.
while hal learns, it is also very scripted ... it has question detectors, religion detectors (if the words Jesus, God, or Lord are used), insult detectors, deduction detectors, command detectors, small talk detectors, business detectors, love detector (if you indicate you love hal) , appology detector, etc. All of these impact its response and behavior ... some, like the insult detectors, actually OVERIDE its responses.
I think I'm seriously failing to communicate because most responses seem to be way off the mark. So I'm going to leave this topic alone for now and if I come up with a plugin that does what I want then you can play with it and you'll see what I'm talking about. If I can't then this will remain a mystery.

But thanks for the help everyone. Its been an interesting conversation.