For me, the use of humor in my presentations is part of who I am away from the podium. It's part of my efforts to maintain sanity at home (raising two toddler boys) and at work (doing PR for a utility). I'm going to goof on Ashton Kutcher whether or not I'm doing a Twitter presentation. I always try to work in the good, bad and ugly of what I've learned so that the pop culture references are balanced by helpful business information. I can't honestly say that I saw more efforts at humor in these presentations than others, so it's hard for me to say that I think it's a trend or coincidence. All I can do is explain my own warped thought processes. I will say as an attendee that humor delivered well will certainly resonate, but it's not critical that a presentation be funny to be helpful.