Meeting size matters
I usually enjoy smaller meetings (20 to 40 people) more than larger ones (hundreds to thousands). Big meetings often schedule sessions on related topics at the same time, so the person who could point out a fatal flaw in the speaker's argument may be in another room. They usually allow only 2-3 minutes for questions, after which people may disappear into the crowd. At small meetings, in contrast, the whole group typically eats together, so there's plenty of time to pursue arguments.
That was certainly the case at last week's meeting on connections among evolutionary biology, anthropology, and economics. Peter Turchin has some discussion and pictures on his blog. With fewer people, small meetings can be held in more-interesting settings than the typical big-city convention center. Last week's meeting, for example, was held at Ringberg Castle, in the Bavarian Alps. Note that Peter's castle photo is almost identical to one I took, at right -- we must have been prowling the same battlement. In the dinner photo, the bald head at lower right is mine.
The Applied Evolution Summit was another great small meeting, held on an island in the Great Barrier Reef, bringing together people applying evolutionary biology to medicine, agriculture, and conservation.
Location aside, grad students would really benefit from hearing the vigorous and usually constructive discussions at smaller meetings. Unfortunately, if everyone brought grad students, the meetings wouldn't be small anymore. Fortunately, there are lots of stimulating discussions at big meetings as well. It's just that they don't necessarily happen in the lecture halls. Poster presentations sometimes generate better discussions than oral talks, but it's also important to include grad students in meals where interesting arguments are likely.