For example, I know the American Historical Association is a Very Major and Important conference, yet I've never been. From all reports I've read, it's a conference large enough to drown in and swarmed by stressed-out interviewees. On the other hand, I'm a Medieval Congress (aka Kalamazoo) regular, enjoy it thoroughly, and run into people I know everywhere I go there. And it's a conference of 4000 people, often enough, which is hardly a small event as juniperus knows entirely too well.
It's difficult to tell in advance what will be good about a conference. That paper with a catchy title you've been eyeing in the program book all week might be extraordinarily dull, cancelled at the last minute, or so abstrusely specific that unless you're an expert on the topic already, it'll go right over your head. Equally, a long and meaningless title might hide behind it a brilliant, witty, and insightful conference paper. The same logic applies to almost any conference-related event: will the plenary, starring many Famous Academics, be monopolized by a Famous Academic whose pet peeve this topic is? Will the dialogue be deep and meaningful? It's a gamble.
Should social factors enter in? After all, if people you know are involved, it's easier to request a copy of the talk directly from the speaker. These days, I try to only consider social factors if there's nothing desperately important to my little subdiscipline which conflicts with it.
I have learned at least two things about conferencing through inconclusive experience:
* Whether or not you attend any good papers in a conference does not necessarily have any correspondance with the number of papers you attend.
* If you're too tired to stay awake for a paper, it's better to go take a nap or go for a walk, than fall asleep in the middle of a session.
When it comes down to it, none of this is particularly useful advice, once you've been to a conference or two yourself. Papers are luck of the draw, unless you've already experienced how good a particular speaker is. But are conferences themselves equally arbitrary?
Conferences go on all the time in any given field. They constantly conflict with each other. Some are free, some are local, some involve transoceanic flights.
Short of previous experience, how do you tell what will be a good conference, one worth attending? What clues do you look for? How do you choose between two conflicting ones? Do you choose on the convenience of geography alone? Price? Do you only attend conference where you will be presenting a paper? Where you know a friend or relative in town you can crash with or at least visit?