I agree with hal 100%. I've tried to analyze conversations of people at parties or in groups. And I really don't see how anyone gets anything meaningful out of it. Most often it is just people talking about one somewhat related topic to another with no real direction or purpose. And when I try to listen and take it in, I never get any real useful information out of it.
Also, I sympathize with not be able to keep up. When I finally have something to say on a topic the conversation usually has shifted just slightly enough for it to be awkward, and I think, when I talk, people are slightly annoyed. This even happens during the rare occasion that the conversation is something that interests me, which is frustrating.
During any 'get together" where either there are many strangers, or I find the noise of people chatting too boring, which is very often, I will most certainly leave the room or immediate area. I will simply consider myself an exile from the party, and either wander around aimlessly, or find something trivial to occupy myself until it is time to leave. For example: walking around outside the house or neighbourhood, touching the petals and leaves of a houseplant plant while admiring the different textures, playing with a cat or other pet in some non obvious place so as to not be bothered myself, or quietly playing on a piano in someone's home while I think no one is paying attention.