David Lang, the Pulitzer Prize–winning composer of the oratorio The Little Match Girl Passion and other works of rigorous idiosyncrasy, lives in the creative realm where quasi-gimmicky ideas can lead to serious, often moving art. Over the 31 years since he co-founded, with the composers Julia Wolfe and Michael Gordon, the Bang on a Can festival of avant-garde music and performance, Lang has devised such works as Crowd Out, a choral piece for 1,000 singers; The National Anthems, a collage of snippets from the anthems of various countries, with the lyrics translated into English; and Symphony for a Broken Orchestra, designed to utilize the flaws in faulty instruments stockpiled by the Philadelphia school system. For his latest work, The Day, which was released in January by Cantaloupe Music (a label he co-owns), Lang mined the lyrics from the Internet, a method he’d already experimented with on Crowd Out. The result is a piece of music so potent that it makes the underlying idea seem not merely clever, but smart.

Lang created the text by typing the phrase “I remember the day that I…” into a search engine and compiling the language that people had used to complete the thought. He selected 301 phrases, varying in length from two to 16 words, and organized them alphabetically—everything from “achieved the perfect engineering drawing” to “wrote my letter of resignation.” The statements are wildly but predictably varied, from universals and banalities like “I was sick” and “I fell in love” to the granularities of individual experience, such as “I could no longer get out of bed” and “I pointed out to the special instruction teacher that I was worried.”

The actor Kate Valk, a respected veteran of the downtown New York theater scene, recites the words—as spoken language, not sung lyrics—over music composed by Lang for the cellist Maya Beiser, a player celebrated for her adventurousness and versatility.

Over the 30-minute duration of the piece, Valk intones the curated statements, one after another, as Beiser plays spare, roaming phrases centered mostly on a single chord (D minor). The piece builds through its subtly mounting intensity and the accretion of cello lines. The music’s simple but uneven phrases—none of them repeated—are similar in mood and style; they feel almost arbitrary and yet, at the same time, utterly natural. As such, they give musical form to the insight posed by the Internet-sourced lyrical content: to someone somewhere, anything can be meaningful.

Lang used a similar method with The Whisper Opera, a composition for which he authored the libretto with materials scraped from the Web and then had the performers whisper the lines to one another—so softly that most members of the audience couldn’t hear the text (and weren’t supposed to). The Day represents an elaboration on this process; it invests collaborations with other people by way of the Internet with a clear creative purpose. Elementally subjective and entirely relatable, it crystallizes both the singularity of memory and the commonality of unshared experience.

Listening to the 301 things that people said they remember in The Day, I realized that I’ve experienced somewhere around half of them. I remember the day I first sat down at the piano, the day I lost my virginity, the day I heard about somebody’s murder. I share no memories of going off to war, or taking in stray kittens, or starting chemo… at least not yet.

Lang hardly introduced content-mining to the craft of music-making. YouTube is full of crowd-sourced mash-ups, including the one that Coldplay made by editing together bits of fan videos for its song “Amazing Day” last year. The fact is, every musician who has ever taken requests, from the minstrels in Homer’s time to the bar bands of today, has tapped the will of strangers to put together a performance. Like the occurrences that Valk recites, mined art is a phenomenon that seems to be made every day. What David Lang has done is make it memorable. Conceptually quirky but utterly relatable, The Day is music every bit as good as its idea.