Although only in his 20s, Alex Sheen already has demonstrated great promise in the nonprofit world—through the very act of promise making.

Grief-stricken by his father's 2012 death, Sheen founded a nonprofit in his honor called Because I Said I Would. The organization uses the powerful act of making personal promises to improve individual lives and the world.

Already, followers have completed 2.5 million of the organization's online "promise cards," pledging to act or create a specific positive change.

Sheen, who will speak at a GameChanger session at the ASAE Annual Meeting & Exposition in August, started by committing to volunteer for a different nonprofit every week for one year and sharing the resulting experiences.

"[P]romises can move the dial for a cause. Keeping a promise is simple. It is actionable," he says. "A text message. A tweet. A Facebook invite saying you'll show up. We can communicate more now than ever before, and with that comes more promises."

Obviously, not all are kept. People hide behind technology, where being held accountable is less likely. And often, "we don't have the courage to say 'no' to something that is asked of us when we know deep down we don't have the time, resources, or interest," says Sheen.

To counter those impulses, his organization launched a weekly YouTube series, featuring people telling stories about an important promise in their lives.

Sheen hopes that the organization's next step will be to establish chapters that "bring good into the world" and help members hold each other accountable for their promises.

What's surprising is who may benefit most. "The small promises you make to yourself are the hardest to keep," he says. "There's no one to hold you accountable but yourself. … This is when you are truly tested."