On the other hand, youtube only has advertisements on its most popular home videos and music videos. The advertisements are at the beginning of each video and must be watched/played in order to see the video. Youtube and Hulu have this in common - their commercials cannot be skipped. Youtube's advertisements are not as long and there is usually only one, because the segments are not as long.
In some instances Hulu tries to cater more to the audience by giving them a choice of which ad they would like to watch; this effort helps ensure that their advertisements have a higher chance of reaching their targeted demographic. Youtube does not have this capability.
In addition, I have also noticed that the Hulu advertisements changed based on when you view the video. For Youtube, the commercials stay the same, regardless of how many times the video has been viewed.
I use both a heavy amount, but differently; they have different purposes. Youtube is meant for music videos, home videos and self promotion, while Hulu is meant for television shows and features DVR qualities.