Kevin Poulsen in Wired:

OkCupid was founded by Harvard math majors in 2004, and it first caught daters’ attention because of its computational approach to matchmaking. Members answer droves of multiple-choice survey questions on everything from politics, religion, and family to love, sex, and smartphones.

On average, respondents select 350 questions from a pool of thousands—“Which of the following is most likely to draw you to a movie?” or “How important is religion/God in your life?” For each, the user records an answer, specifies which responses they’d find acceptable in a mate, and rates how important the question is to them on a five-point scale from “irrelevant” to “mandatory.” OkCupid’s matching engine uses that data to calculate a couple’s compatibility. The closer to 100 percent—mathematical soul mate—the better.

But mathematically, McKinlay’s compatibility with women in Los Angeles was abysmal. OkCupid’s algorithms use only the questions that both potential matches decide to answer, and the match questions McKinlay had chosen—more or less at random—had proven unpopular. When he scrolled through his matches, fewer than 100 women would appear above the 90 percent compatibility mark. And that was in a city containing some 2 million women (approximately 80,000 of them on OkCupid). On a site where compatibility equals visibility, he was practically a ghost.

He realized he’d have to boost that number. If, through statistical sampling, McKinlay could ascertain which questions mattered to the kind of women he liked, he could construct a new profile that honestly answered those questions and ignored the rest.