As a degreed net Political Scientist (hey, that stupid degree should count for something), allow me to opine that at this early stage of the campaign season, the extremists among the candidates always make the biggest noise, because the only people really paying attention at this point are the True Believers.
The Democrats have got a LOT of issues to sort out before they take their show on the road. When a neo-Stalinist like Kucinich is wowing the crowd, it's got to scare hell out of those Democrats that realize how far they have to go to come up with somebody actually electable.
Just like poop-eating dogs, Democrats can never resist returning to their steaming pile of utopian socialist ideals for another snack.