A LOT of people do not research candidates online. All they know is what the pundits tell them on FOX or CNN, or with some people, they know nothing past their own party-based preconceptions until they see the debate.
There are also a significant number of people who don't really follow much of what is being said, but rather base much of their opinion on their perception of the candidate's character. I remember a woman telling me that she voted for W. Bush because he seemed trustworthy and genuine. Older people, especially, seemed to be influenced by persona, and some believe many women are, as well.
I think this is shown by how many people cite the way the candidates acted, such as being nervous or grouchy, when they decide who "won".
