ZDoggMD's rapping video about safe sex is a beautiful example of how to grab the attention of your target audience using a medium and tone that they can get down with.
While you are on ZDogg's site, check out their first News Per Rectum podcast, Potty Mouth (punchline: "I gave a crap today"), about fecal transplants for pre-diabetes. Coincidentally, our first podcast also had the word "potty" in it (Podcasting Makes You Potty).
So, I gotta say... these guys are hilarious. Educational (sometimes marginally so) while being thoroughly entertaining and mildly offensive. Their production value is quite good, as well.
That being said, I don't expect us to follow in their vlogging footsteps. But keep an eye on these guys.