A few years ago, Mr. Wong was described in the news media as the youngest person ever to receive venture capital funding. But a couple of younger founders came along — “and then Nick broke all of our records,” Mr. Wong said on Monday.

Among the attributes that helped Mr. D’Aloisio, he said, was a preternatural ability to articulate exactly what he wanted Summly to be. “There were no umms, no uhhs, no hesitations, no insecurities,” Mr. Wong said.

Mr. D’Aloisio, for his part, sounded somewhat uninterested in answering questions about his age on Monday. He acknowledged that it was an advantage in some pitch meetings, and certainly in the news media, “but so was the strength of the idea.” He was more eager to talk about his new employer, Yahoo, which is trying to reinvent itself as a mobile-first technology company (having dropped the digital media tagline it used before Marissa Mayer became chief executive last year).

“People are kind of underestimating how powerful it’s going to become and how much opportunity is there,” he said.

For a company that badly wants to be labeled innovative, those words are worth a lot.

Mr. D’Aloisio’s father, who works at Morgan Stanley, and his mother, a lawyer, had no special knowledge of technology. But they nurtured their son’s fascination with it and he started coding at age 12. Eventually he decided to develop an app with what he calls an “automatic summarization algorithm,” one that “can take pre-existing long-form content and summarize it.” In other words, it tries to solve a problem that is often summed up with the abbreviation tl;dr: “too long; didn’t read.”

Summly officially came online last November. By December, Mr. D’Aloisio was talking to Yahoo and other suitors.

Yahoo said in a statement that while the Summly app would be shut down, “we will acquire the technology and you’ll see it come to life throughout Yahoo’s mobile experiences soon.”