Lori, I'm not sure if there is hidden subtext other than the Darwinian. Parties are about treading water artfully, surviving them without emotional or actual hangovers. And sometimes people who don't much like one another pretend at least to be able to occupy the same space for a moment or two. Other than that, I believe from what NT friends tell me, that parties are about as uncomfortable for them as they are for me. They say they can tend to struggle with small talk and with feelings of boredom. They may be better at hiding it!

Having organized parties as part of my career for many years, I have studied them and understand their importance. One of my favorite party conventions is the one where people "blame it on the wine" and broach difficult subjects with the understanding that all will be forgiven later. Twenty years ago, I had a CEO corner me and press me about whether my boss was a lesbian, and I told him, "I dunno. Ask her. I think she can answer questions on her own." He was annoyed with me, and I said, "Really, this conversation has gone on long enough. It's bordering on the voyeuristic, and that's not becoming of you." We were able to talk some more and all was fine.

One of the best preparations for party topics was to participate in Toastmasters, where I learned to cough up interesting tidbits in the news, things I'd noticed that seemed out of place, unusual jokes. These I'd use as icebreakers. Sometimes that's really all the conversation would be, a few exchanged lines before people moved on to greet and mingle with others, and sometimes, the people I spoke to would have stories of their own and we'd discover a common interest and talk for a while.

I'm a bit slow to transition, so I need to watch my tendency  to become too involved with a topic. At parties, people are pretty distracted, and movement from group to group can tend to be important. 

And yes, I think sometimes people talk just to talk, either because they have had too much wine or because they are a bit nervous. 

Sorry, I'm not NT. Just chiming in!

True, true, the comfort issue is important for NTs.

People don't like when people don't talk, so they feel obliged (unconscious at times) to fill in. Otherwise they interpret it as a lack of interest or that the two are not getting along well. Again it relates to avoid that others are feeling embarrassed or that they realize you are not interested in them, or that you don't want to feel this way too. So people talk easy topics where both can have things to say. Not knowing what to say is also a potential risk. When people don't have anything relevant to say they feel they need to move on, so they avoid feeling stupid and that the other person come to realize they have no longer interest in talking about the current subject or in them. That is also why rules of etiquette recommend to avoid talking about politics, religion and money. Because all of them can potential upset people and show disagreement among them. In superficial encounters, disagreement is not well dealt with. Thought you can have healthy debates where everybody enjoys arguing about a topic. But usually in these discussions, it never involve personal issues.

Now I think spectrumites may have less internal conflict about leaving other feeling bad or uncomfortable, because spectrumites tend to be straight forward (a great quality i love it and tend to be that way too with age). Spectrumites tend to show when they like or don't like topics or people. I think that is something some NTs dream to do. Don't NTs admire heroes in movies or other strong characters who can "rule" and be free spirits? It can be a privilege to not have to put yourself in those kind of situation where you don't care about the person but have to put up with... spectrumites are free in that sense. Now, it doesn't mean other NTs will deal with it well... LOL

I love being able to go to the bottom of things (have deep conversation) and talk without worrying about keeping people comfortable or not. But you gotta be careful not to talk people ears off. As an NT or not (not sure) sometimes, i realize that people show interest, to be polite, but they aren't willing to go far, and so they start showing some signs thay are not so interested anymore. ex: stop contributing to the conversation (feeding the topic eg. questions or opinions), start looking away or at their watch, start saying things like "great", "well", "okaaay". so it means they are ready to move on. They might also start physically move back or on the side, showing they want to move on. At parties, the best way to stop an uninteresting conversation is to use excuses. You can say "I'm sorry but I need to use the restroom". or you can initiate a shift in the dynamic, by suggesting to have a drink or a toast, etc. this can change topics or discussions. because you can initiate new topics "So, you have been working on this website..." also if there are lots of people, you can always integrate more people in the small group and initiate new conversations. You can say "this is Bill, have you guys met?" and then you can be sure the previous conversation is over.

LOL

From my experience, it these "fluff" conversations can serve two purposes. The first, as has already been discussed, is the general "need" to be talking and interacting, as silence can been seen as awkward. IT's one thing on an elevator to not really talk to someone, but at a social gathering, the expectation of interaction makes people feel the need to talk to one another and interact.

However, sometimes (but not as often), such fluff conversations which people use to try and get an understanding of someone else. The way in which someone reacts to a question, both in content answer and body language, etc. tend to give someone a feel for another person, at least as they react towards them. I guess the best way to think about these types of situations as like much more subtle versions of those scenes you seen in films where the protagonist goes out of their way to see the antagonist in a social situation to get a sense of them (i.e. various James Bond films where he goes to see the villian without revealing he is a spy, etc.), in order to get a sense of who they are without direct confrontation. Again, this isn't often, and I have found that it tends to sometimes be more of a male thing or at work parties, etc., but it does happen from time to time.