it's weird, because we pay with our attention. Would people "pay" for a 7 second video that shows exactly what they want perfectly clearly, by watching a 30 second advertisement? Maybe yes, maybe no, but those 7 seconds are more valuable than 2 minutes of filler, during which you have to watch the ad anyway. I think there's room for some kind of micropayment for short tutorials (7 seconds) but I think attention (attention to ads, i.e. sitting through one) might not be it.