I'm big on analyzing polls, but you always have to remember the human factor, and take polls with an enormous grain of salt. Many people (a) are uninformed; (b) not that bright to begin with; and (c) not that honest. To wit, this "man on the street" interview segment from the Jimmy Kimmel show, in which he asks people who won last night's debate before it happened!
Interestingly, none of these people seem stupid. To the contrary, they are the epitome of the liberal voter... pretending to be smarter than they really are, and offering what they think is the politically correct opinion.
There's a lot of that going around. In fact, I'd say this attitude explains the 2008 election... people voted for Obama because they wanted to feel smarter, and cooler, and hipper, and more tolerant, and more cutting edge than they really are.