Why does some video content grab viewers by the throat, compel them to watch and then suck their mouse towards the bookmark/email/blog about link?
How do we get us some of that mojo for our productions?
To me, the reason some online videos grab us is no different than why some more traditional video experience (movies & TV) compel us to watch and tell our friends. Online video is inherently more "sharable" than traditional, so it takes much less effort to tell all of your friends.
The second part of the questions asks how content providers can create videos that we, the viewers, want to share. That's a tall order, as everyone's triggers are tripped by different things. Some of the most "viral" of videos I'm not a fan of, and I'm guilty of sharing things with others that cause them to look at me like the RCA dog. In my mind, it remains a uniquely personal experience that is sometimes resonant to the proclivities of many others. I'll staunchly stand by my position that content creators should strive to create the very best content that they like as their primary goal. It's difficult to judge what everyone wants, but you should have a pretty good handle on what you want.
Now for your part in this experiment: As mentioned earlier, this is part of Chris Brogan's 100 Comments experience. While you are welcome to post your comments here, the idea is to post comments on the original feed to get to critical mass with lots of people's networks. I've posted my comments there exactly as I have written above.