Sadly this would be a good way to get to youth, but the kids on YouTube won't listen to them. Most of the people on YouTube I think are 13-17 year old jr and High (skrewl) students. You can tell by the comments if you use a word with more than two syllables they don't understand. Also do a quick search for George Bush Vs. about any liberal he is Bush is bashed about as bad on YouTube as DU. It's too trendy nowadays to hate Bush and Republicans everyone is with the cause de jure.
I generally agree, but have you seen the Geriatric1927 videos? This is an old guy from England who basically just sits and talks about his life. No gimmicks, just talking like someone's grandpa. The kids seem to love it, tho some of them should be listening to their own grandparents while they have the chance.
I watch YouTube (I'm 53) because you can get old tv like SCTV and because as a doctoral student in information science, I'm interested in the diffusion of technologies. I'm very interested in what kind of stuff winds up on YouTube and what kind of people, people you wouldn't expect like Geriatric1927, use it.
I don't bother with the political stuff. As you say, these are mostly young people and I just don't care what they have to say about something as important as running the country. Obviously their 'change the government now' rhetoric doesn't match their actions or they would have turned out in greater numbers at the last election.