Women make up a majority of the U.S. voting-age population, registered voters, and actual voters. These facts explain why both major political parties – Democrat and Republican – and women's advocacy groups from across the ideological spectrum worked hard to mobilize women voters in 2008. Democrats did a slightly better job than Republicans of getting out the vote – the reverse of 2004.

Democrats, particularly the Obama campaign, were more successful at tapping into the powerful new media of the day – social networking sites and online video. YouTube, Twitter, Facebook, MySpace, and Flickr each played a vital role in keeping voters, particularly younger ones, interested in the presidential election from start to finish by revolutionizing modes of communication between the candidates and the electorate. In addition, the extraordinary involvement of “celebrity” women (candidates, spouses, entertainers, and news media stars) made the campaign even more intriguing for women of all ages.

At the same time, the highly competitive, protracted fight between Hillary Clinton and Barack Obama for the Democratic Party's presidential nomination, followed by Sarah Palin's nomination as Republican John McCain's vice presidential running mate, made it crystal clear that even women within the same political party are not always a politically cohesive group. In the early stages of the campaign (primaries and caucuses), many Democratic women's votes were split between Obama and Clinton. And Palin's nomination as McCain's vice presidential running mate alienated some moderate GOP women, prompting them to vote for Obama.