Stephen Pinker writes in his book How Minds Work that "the emotions are mechanisms that set the brains highest-level goals." This, it seems, is a good description of why small, mission-driven nonprofits exist despite the innumerable difficulties of keeping such an operation afloat. It's also an essential idea to consider when advertising your organization.
People are drawn to imagery and emotions that inspire them to work for a cause. If you have ever been saddled with the task of creating ads or promotional material for your organization, you would do well to keep these emotions — not facts about your job or accomplishments — at the front of your mind.
This concept is just one idea among many in an immensely useful e-book published a couple of years ago by Cause Communications called Why Bad Ads Happen to Good Causes. It should be in every nonprofit office (unless you have the luxury of an ad department to think about such things). It covers broad ideas like the above, but it also goes into detail about using layout and text to keep people reading and engaged in your message. And it has great reviews of nonprofit ads over the last 10 years. It is, in short, an eminently readable advertising textbook for nonprofits; check it out before your next ad deadline.