I haven't been to any scientific conferences so far this year, and I have to admit that I in some ways I haven't felt the lack. There are a few meetings that I enjoy more than others (Gordon conferences and Keystone meetings come to mind), but there are others that I'd have to be paid extra to attend. Some of the really large ones have been out of control for years (Society for Neuroscience? I'm talking about you.)
You can pick up some good information at one of the better meetings, but even then it can be a strain. Scientific presentations can often be mistaken for a work of the devil: here, I have some important and interesting things to tell you. So I'm going to run it past you once, from fifty feet away, in the dark. Sound good? Or more like a technique to deliberately impair communication? Your best shot is a good poster session or a one-on-one talk, and the Gordon or Keystone type meetings I mentioned earlier are the best ones for that kind of contact.
It doesn't help that many scientists are such notorious speakers. I've had very bad times, there in the dark, watching someone who's clearly using his slides as mnenomic devices ("Next slide, please. . oh, yes, that's right, here's where we were trying to synthesize. . .") or someone who reads off every word on every slide, adding not a syllable of information along the way.
My patience for such things was never very well stocked, and I've run completely dry in the last few years. When I'm listening to a poorly delivered talk, or one on a subject that turns out not to interest me at all, I just sit there thinking of the time that's going to waste and what I could be doing.
At least I'm awake, though. I recall one seminar in graduate school where the visiting speaker pretty much put everyone into a vegetative state from about the second slide. The floor was thrown open to questions at the end, but an embarassing silence ensued. The faculty member who introduced the speaker caught on very quickly, and popped in with a question of his own: "Actually, one of your reactions reminds me of something one of my students is trying right now - right, Paul?" Dead air. "Paul? That addition to the acrylate?" Nothing. Elbows begin driving into Paul's ribs, waking him abruptly back in the next-to-the-last row: "Uh. . .what was the uh, question?"