Utube comedians are largely responcible for YouTubes enormous success and if you look closely, so many of the site views can be attributed to clips that these people have produced and stared in only second to music. Recently they had a huge event on live where the performers where mainly composed of comedians that perform music mainly.
Its not hard to do comedy work, the rule is actually fairly simple, yet not always easy to perform and it goes a bit like this. If you walk up to someone and tell a funny joke they will say "that was a funny joke", however if some time passes and you tell a few joke in the meantime a hook point will be reached where its no longer the joke that is funny, its the person. Quite amazing when you think about it or are trying to become a comedian.