“My First Time,” at New World Stages, is “inspired” by the Web site MyFirstTime.com, on which people post what are ostensibly tales of their first sexual experiences. Produced and directed by Ken Davenport, the show is a series of monologues and one-liners written by Mr. Davenport and, as the Playbill puts it, “Real People Just Like You.” If, that is, you’re the type to write about your sex life, or your fantasies, online.

Cobbled together from entries on the site, “My First Time” means to be fun and free-spirited, and sometimes it is. That it rises to that level at all is a credit to its talented cast of four, particularly Kathy Searle and Josh Heine, who manage to locate humanity, humor, and life inside some truly deadly prose. But it’s poor Ms. Searle who’s saddled with the line, “Wherever there was the urge, we merged,” whose banal crudity is about par for the show.

Taking inspiration from a Web site is not an inherently bad idea — Ars Nova’s current production, “The Wikipedia Plays,” for example, uses entries on that site as a jumping-off point for a lively cycle of shorts that works beautifully. Charles Mee, not a playwright to sneeze at found material, employed Web logs and other online texts to excellent effect in his recent requiem, “Gone.”

Nor is frank sexual discussion necessarily an ill-advised raison d’etre for a theater piece, as Eve Ensler’s “The Vagina Monologues” proved.

None of those works, however, overlook the importance of the writer. Each of the 17 playwrights in Ars Nova’s Play Group penned a short for “The Wikipedia Plays,” some of which are only tangentially related to the site’s entries. Mr. Mee and Ms. Ensler, though using words that were not their own, understood the importance of choosing them well, and the need to sculpt the pieces they made with them.

In contrast, the raw material of “My First Time” too often sounds like it would be right at home on another Web site, Penthouse Letters — and not only because the amateur writing is often leeringly graphic. These stories are also just about as credible as the famously fantastical letters to Penthouse.

That’s part of the reason that “My First Time” works far better when it’s funny: It’s impossible to know which stories are true, so they might as well be amusing.

In fact, one of its jarring descents into sincerity is with the dying-brother-in-the-car story, whose narrator makes it clear with her self-righteous final line that you’re a prude if her tale makes your skin crawl. “I have no interest in approval,” she says. Those words might sting if there were any way to be sure that the person who posted that story on MyFirstTime.com was telling the truth, but smart money says she or he wasn’t.

Affirming our common humanity is one of the time-honored goals of theater, and certainly “My First Time” — though it deals only glancingly with the less-than-sexy aspects of sex, like contraception, sexually transmitted diseases, and unintended pregnancy — makes a decent argument that we’re all sexual creatures.

It also, quite unintentionally, makes the case that the telling of some stories is better suited to the glow of the computer screen than to the glare of the stage lights.

Open run (340 W. 50th St., between Eighth and Ninth avenues, 212-239-6200).