Since April 2007, New York magazine has posted online sex diaries. People send in personal accounts of their nighttime quests and conquests. Some of the diaries are unusual and sad. There’s a laid-off banker who drinks herself into oblivion and wakes up in the beds of unfamiliar men. There’s an African-American securities trader who flies around the country on weekends to meet with couples seeking interracial sex. (He meets one Midwestern couple at a T.G.I. Friday’s.)

But the most interesting part of the diaries concerns the way cellphones have influenced courtship. On nights when they are out, the diarists are often texting multiple possible partners in search of the best arrangement.

As the journalist Wesley Yang notes in a very intelligent analysis in the magazine, the diarists “use their cellphones to disaggregate, slice up, and repackage their emotional and physical needs, servicing each with a different partner, and hoping to come out ahead.”

Often the diarists will be on the verge of spending the evening with one partner, when a text arrives from another with a potentially better offer. To guard against not being chosen at all, Yang writes, “everyone is on somebody’s back-burner, and everybody has a back-burner of their own, which they maintain with open-ended texts.”