All anecdotal evidence i've seen agrees, I made an explanation video for one of my websites , and when it was over two minutes long no would even start it. I split it up into two videos (<a href="http://www.youtube.com/watch?v=SLJHPMxgAWU" rel="nofollow">http://www.youtube.com/watch?v=SLJHPMxgAWU</a> ), and since splitting the videos I've out of 308 combined views i've got 195 new users.<p>I also helped out a little with waterloolabs, they make youtube videos of them doing crazy stuff, like playing half-life with real guns, or driving a car with an iphone. Hunter has always said "under three minutes" especially for "the tube", and looks like wistia's metrics agree.