Yeah, I think it’s conceivable that Hillary finally started to get through with her message along these lines. It also doesn’t hurt to have your husband out there lying through his teeth. I think the best explanation is some combination of these factors: a slightly re-tooled approach on the experience issue from Hillary, negative and false campaigning from her and Bill, and women taking more notice of the misogyny of the media and sympathizing with Hill. YMMV.
Or it could be the independents thinking that they really wanted McCain to win.
Or simply assuming that Obama would win with or without their vote and wanting to make their votes count.