But I must say I've been impressed at the Obama campaign's ability to produce email subject lines that ignite curiosity. As another fundraising commentator pointed out (I'm sorry, I can't remember who gets the credit), one method that the campaign has used is to have the emails come from different sources -- Joe Biden, Michelle Obama (I usually open those), various campaign staffers, and Barack Obama himself. Even if they're really written by a communications person, that added sense of individual perspective goes an amazingly long way toward making me want to hear what they have to say.
Many of the emails' subject lines are also cleverly suspenseful -- things like, "Last chance," or "Our best shot in Ohio." Or they offer videos, or other special features.
Obviously, their campaign didn't invent these techniques, but they've provided a look at how any nonprofit can, despite emailing people on an almost daily basis, keep those emails from becoming an unwanted and repetitive barrage.