The viral ad that has made mothers everywhere cry and children everywhere remember they need to buy their mom a Mother's Day card had an unlikely start.

The advertising agency writer who came up with the idea to present being a mom as a thankless job that few people would apply for came from a woman who is not a mother herself.

"Our writer went home over the Christmas break and spent time with her brother and sister-in-law and saw her that her sister-in-law never stopped going 24/7 with her kids," said Jon Ruby, vice president and creative director at Mullen advertising agency. "She realized being a mom is really a job and probably the world's toughest job."

The result of the writer's Christmas break with her family is a four-minute YouTube video that has garnered nearly 1.5 million views since it was posted Monday.

The video shows a handful of people being interviewed for a "Director of Operations" position that includes demands like standing up almost all the time, constantly exerting yourself and working from 135 to unlimited hours per week with no vacations, no time to sleep and no salary.

"Is that even legal?" one applicant asks during the interview.

The job, it is revealed at the end of the video, is for the position of mother. Mullen Advertising created the ad for its client, card-maker American Greetings.

"Our assignment was to get people to do something for moms this Mother's Day," said Ruby, who works in the agency's Boston office. "The idea became to treat the idea of being a mom as a real job and place it out there with all of these requirements and see what happens."

Mullen placed ads for the "Operations Director" position in 14 newspapers, 29 Craigslist markets and on Google ad words, reaching an estimated 2.7 million people.

Out of the millions who saw the ad, 24 people applied for the position on the website Rethom.net, or "mother" spelled backwards.

"One applicant wrote in the comments, 'This sounds like the mother of all jobs,'" Ruby said.

Ruby and his team picked the best applicants from the 24 to be "interviewed" on camera. Their responses when they found out what the job truly was were nothing but positive, according to Ruby.

"You can see the emotion," he said. "As soon as we revealed that the job was about moms, it was like, 'Oh, we get it. Great."

"There wasn't one negative response in the group," Ruby said.

Ruby says each of the "applicants" in the video received a "nominal" compensation fee. Each of the 24 people who responded on the website will receive a free Mother's Day card from American Greetings.

The video is much longer than most viral videos but Ruby says that was because the qualifications for being a mom were so long and the applicants' recollections of their own moms so great.

"It's really the fastest four minutes I've seen," Ruby said. "There's that curiosity aspect to it as you're watching it, and you have to stay to the end to see the reveal."