(6) Networking. I know this can be a bit of a buzz-word (along with synergy and paradigm), but I think the most important part of these meeting are the fact that you are finding potential co-authors, future co-conspirators and available letters of reference.
Speaking from my past, the most useful meeting we attended was one where neither my wife or I was on the job market or presenting. It was the year before graduating and we decided to go so we could get a feel for the process before actually being on the job market. We met a few fellow grad students and went out for lunch and played hookey from the meetings one afternoon.
The following year when we were on the job market, we met our a friend from the previous year who introduced us to the department chair from her undergraduate institution. That connection let to my wife being interviewed and subsequently hired there. Four years later I was hired. Two tenure track jobs as a direct result of a social connection made at the conference.
Of course, there is no way to know which contact you make that will turn out to be the important one and there is no guarantee that your story will have the same happy ending. But the people you meet (and your ability to turn those connections into jobs, grants or research articles) will be the determining factor in your future success.
