I love this case study as it's an example of testing & marketing in the political world. Obama was the first president to really reveal his marketing strategy...View More to the outside world. He took mega advantage of the internet & played email marketing very smart. The fact that the subject line "I will be outspent" was the most effective was of little surprise to me. Many people feel VERY strongly about politics & when you're on the president's mailing list & are ready to donate, it shows you are committed  & are somehow tying your life into the success of his campaign. When Obama stated he will be outspent, in the eyes of the supporter, it was like they were a potential failure & disappointment too. It's not like Obama would be just outspent. The supporter would feel like they were outspent & as many in the marketing world know, fear & pain creates more action than pleasure. http://www.wired.com/opinion/2013/06/dont-dismiss-email-a-case-study-from-the-obama-campaign/