It’s not often that one simple idea, posted online, can lead a person around the world to help people change their lives for the better.

But that’s just what happened to Alex Sheen, and the idea couldn’t be simpler: Keep your word.

Sheen is the founder of “because I said I would,” a nonprofit social movement, as he calls it, that is dedicated to helping people keep their promises, both big and small.

Sheen shared his message with people in the Sheraton Hotel’s Amos Dean Ballroom at the on Wednesday night.

The event was the second cosponsored event between Dance Marathon and the University of Iowa Lecture Committee.

Madison Traviss, the event director for Dance Marathon 21, said she wanted to invite a speaker such as Sheen because his message of keeping promises goes hand-in-hand with Dance Marathon’s commitment to helping cancer patients and families.

“I think having his message of keeping promises and following through on promises just gave that the extra step for students to really understand what commitment they made,” Traviss said.

Sheen’s work and message, coupled with his laid-back, conversational style of speaking appealed to Dance Marathon and the Lecture Committee, Traviss said.

“Having his message accompany our fundraising just made sense,” she said.

UI Lecture Committee head Nathaniel Richmond said the partnership with Dance Marathon made sense because of its large following and its big impact on campus and in the community, he said.

Sheen began by talking about his father, who, he said, was normal in every way — except for one thing.

“For everything that made my father average, normal, everyday, there was one thing that he did exceptionally well, and that was keep his promises,” Sheen said.

The effect this had on Sheen’s life wasn’t fully realized until tragedy hit his family hard: Sheen’s father was diagnosed with cancer.

After a brief recession, it returned even worse, and eventually was fatal; Sheen’s father passed away on Sept. 4, 2012.

He was asked to deliver his father’s eulogy, titled “because I said I would.”

After that, he came up with the idea of promise cards.

The cards were blank on both sides, except on one side, in the lower right-hand corner, were the words, “because I said I would.”

Soon after, he posted online that he would send five of these cards to anyone in the world to help them keep a promise.

Since that day, his idea of keeping promises has gone viral, with more than 2.1 million cards being sent to 105 countries.

He has appeared on CNN, the “Today Show,” and ABC World News.

Despite the barriers in language, culture, and language that exist, Sheen said the popularity of his idea can be attributed to one idea.

“We all understand the value of a promise,” he said.