“And I’ll be honest,” he said. “I don’t want to stay up until 4 a.m. any more at shows, and you can annotate lyrics during the day.”

The magazine will be hiring a new critic, its editor, David Remnick, said in an email Sunday, though Mr. Frere-Jones may contribute occasional articles.

Genius has also hired another journalist, Christopher Glazek, to focus on politics and culture annotations, Mr. Zechory, 30, and Mr. Lehman, 31, said. The site will continue to hire people with expertise in particular subject areas, aiming to bring in more users from online communities obsessed with particular topics.

Genius’s expansion marks the latest merger of the tech and media worlds, and helps to fulfill a prediction made by one of the company’s funders, Marc Andreessen of the venture capital firm Andreessen Horowitz, that the definition of journalism might broaden to include jobs outside of traditional writing and editing.

“My remit is going into the lyrics site and building a team,” Mr. Frere-Jones said. He added that he planned to initially add three or four people, and that their precise role was hard to describe, though the skills were rooted in journalism. Mr. Frere-Jones will use his contacts in the music industry to bring artists and writers into Genius, seeking a critical mass of influential names for “that Twitter moment when suddenly the smart kids stop holding their noses up in the air and they take part, and it just improves.”