Toby Fallsgraff, who oversaw the Obama campaign's email efforts, said the campaign raised more than $500 million online via 4.5 million donors, averaging $53 a donation.
The campaign spent a lot of time testing subject lines. On June 26, an email sent from the President with a personal acknowledgement that he would be personally outpsent in the election raised a lot of money. Testing showed that the email with the same message with a different subject line raised half as much money.
But what did best. "Hey" was the "go to subject line," Fallsgraff said.
"Light swearing" also did well. On the day of the anniversary of the passage of ObamaCare, David Axelrod sent out an email including "Hell yea" in the subject line.
Overall, the campaign found a "casual" approach worked.