As with John Edwards, I don't understand the big deal about this guy.
I think the big deal is probably about the same as with Edwards, except the bonus fact that he's a "person of color." I'm sure the old leftists who operate the media are positively moist with the anticipation of touting someone who is openly socialist and black. They are also loving the whole "giant killer" aspect of Obama's run. The hardcore left doesn't really like Hillary all that much, so playing her off against Obama is sure to result in plenty of drama that will sell TV commercial airtime on the news.
All things considered, Obama is really no big deal. Just another left-wing power whore.