Vice presidents are usually new to the country, unless you think the public is hip to who the Mondales, Quayles, and John Edwardses are.
Palin was one of the hottest political properties in the country, being the most popular Governor in the nation, and that speech on the day that she was chosen (pre convention)was perhaps the best speech ever given by a woman in America. Palin has continued to set new standards for drawing audiences from the very first day of the announcement of her being chosen. That is how she has driven this conservative movement.