Video - What makes a good one?

I’m preparing to go to another one of our seminars, if you’ve attended any in past I’m the one pinning the speakers into a corner trying to extract their juiciest piece of best practice advice for you dear readers. However each event is an experiment, I was given a video camera a few months ago by my editor and told to go for it. And that’s what I’ve been doing, but am I doing the right thing?

What do you look for in video? Simple best practice advice lasting no longer than 2 minutes in total or a more detailed and longer video? Do atmosphere shots (delegates nodding heads, or mingling) annoy you or make for a more engaging video? Are you even bothered?