"Although I don't actually claim that Bush won because of usability, I do think that wise use of email newsletters contributed to his victory. I analyzed the email newsletters sent out by both candidates in the week prior to the election. (...)
As this analysis shows, Kerry supporters were bombarded by repeated fundraising requests, to the extent that many of them probably tuned out the newsletter in the final critical days. Although the Internet is great for collecting money from the masses, there is a limit. Kerry exceeded it.
Bush sent more messages than Kerry asking supporters to get other voters to go to the polls and vote for him. This is a more appropriate use of the newsletter medium because it connects emotionally with subscribers. Being treated as an active participant in the civics process is more motivating than being regarded as an open wallet."
Daily Kos: How BC04 made better use of its email list, 8 nov 2004
"Subject lines were universally lame, with Kerry having the most user-repellant subjects, like 'Tonight,' 'Don't stop now,' and 'Deadline almost here.' Why would anybody think that those messages were anything but spam? Bush had somewhat better subject lines, like 'Kerry's Flip Flop Olympics,' and 'Participate in W ROCKS in Alameda County,' though he also had content-free subjects like 'Brace Yourselves.' (20 sep 2004)