1) her relatively unknown status diverts the positive press from the DNC as media scrambles to write "Who is Sarah Palin?" stories. And what they write will have great appeal.
2) The country is full of Republicans who, in light of the current political disaster, are looking to save face. A vote for Obama forces them to admit they were wrong. A vote for McCain/Palin provides an opportunity to be less wrong.
3) By choosing a candidate with such strong ethical credentials, it grants McCain integrity points.
4) A woman provides "I'm not a racist or misogynist - I love that she's a woman" points.
5) She appeals to womaen (over half the voting population) who like to identify themselves as Christian feminists.
Do I need to go on?
It's ironic - the best counter to Sarah Palin is Hillary Clinton. But she's not on the fucking ticket.
Many liberals on this board are going to be slow to realize the level of "sparkle" she provides to a ticket that desperately needed some. But they underestimate this pick - she has substance; over time, they'll figure it out. She is the perfect choice. If only Obama had made the perfect choice to preempt it...