For my own experience the quantity and length of ads on Youtube has reached the tipping point where I start dreading even going to Youtube anymore. It's fine to see a 5 second ad for a video I know I will enjoy, but the ads on the 'speculative' videos where I'm just hopping around looking for something interesting to watch are beyond ridiculous. The other day I watched 10 crappy videos in a row, all of which had at least a 5 second-then-skip ad at the beginning, and one with a must-watch 15 second ad. That totaled one minute of ads for what turned out to be zero seconds of entertainment.