I also think it's worth mentioning that we can model as dancers the behavior we'd like to see as callers. Socializing and catching up with friends is excellent, but when I'm dancing, I make an effort to always quiet down and listen to the caller whenever they start speaking, and perhaps gently direct others' attention to the caller (not with a "shh", but by excusing myself from conversation and looking at the caller). My hands-4, and sometimes those around us, will generally take the hint. I think this modeling is especially important around new dancers--we want to send the message that the walkthrough is something to be listened to, not something to be chatted through (which is just rude, and even if you're experienced and don't need to be paying full attention to the walkthrough, other dancers in the hall do need to pay attention, and you're making things harder for them).
Another thing I try to do, and try to encourage my friends to do: if I do need to teach from the floor as a dancer (say, some beginners are getting hung up on a new move), do it with as few words as possible, preferably non-verbally. Again, the more you talk in line--even if it's for a good reason--the harder it is for the people who most need to pay attention to the caller to do so. Teaching verbally from the floor also diverts attention and authority from the caller in ways that nonverbal teaching does not. So often as a caller I've seen a problem in the room (in a walkthrough or a lesson) and tried to correct it, only to find multiple different experienced dancers explaining the move to small groups, so that I can no longer get the attention of the room, and it takes much longer to solve the problem.