EVEN THOUGH I LIVE IN MANHATTAN, I'M AN OUTDOOR TYPE OF GIRL.

I've trekked through Nepal, gone on safari in Africa, and (in case things got too wild) learned kung fu from a Shaolin monk. I cook a mean coq au vin on a camp stove, and I don't wear mascara when I surf. But last November I turned 36, and I still hadn't met the right guy—by which I mean a real guy.

I decided I was through playing barstool roulette and hanging out at my local Barnes & Noble. I was sick of dating fussy intellectuals and well-groomed metrosexuals obsessed with pedicures and designer jeans. It was time to find a mountain man, a guy who could chop wood, rappel down an ice face, and run a wild river. Why not hunt for him the 21st-century way—on the Web?

I certainly had nothing to lose: I'd run screaming from enough freaks I'd met the old-fashioned way. In the past few years, I'd gone out with a media exec who was afraid of the ocean and brought his mother along on our second date. I'd let myself get picked up on the street by a tall, handsome high school teacher who took me out for a drink, ordered red wine, and proceeded to sip it through a straw so he wouldn't stain his teeth.

Sure, I was worried about attracting porn addicts and other sleazoids. But friends assured me that dating online was cool, safe (if you're smart), and—considering the numbers—completely logical. Today, more than five million singles are shopping in the U.S. digital meet market; Match.com, one of the largest online dating services, claims as many as 15 million members worldwide. Specialization is everywhere: There's TallPersonals.com ("Size does count!"), for the "height-blessed"; DateMyPet.com, if your dog is the center of your life; and AshleyMadison.com ("When monogamy becomes monotony!"), for cheating spouses.

And now, thanks to Greg Prosl, a backcountry snowboarder and competitive mountain biker from Seattle, there's also SingleAndActive.com—a hookup hub for adventurers and athletes. Prosl, 41, says he launched the business in the fall of 2004 after suffering one too many online encounters with women who shared none of his outdoor passions. "Most of the generic dating sites aren't set up to let people talk about their sports and list the ones they like most," Prosl told me. "On SingleAndActive.com, you can."

The site isn't huge—there are only about 10,000 members, most of them located in major U.S. cities—but the male-to-female ratio is three to one. I hit SIGN UP NOW.

The rest is easy. Membership is free. You don't need to take complicated personality tests or bare your soul about why your last boyfriend/girlfriend didn't like your cat, why you don't want to have long talks after shagging, and what celebrity you most resemble. All you have to do is pick an anonymous screen name, offer some stats—age, height, and zip code—and, if you want, write a few sentences of self-description. Most important, you rank your favorite sports. If other members like your profile, they send you an e-mail—a "flirt" as the site calls it.

I pick "cosmocamper" for my name, because of my citified ways. I slice five years off my age (who doesn't?) and name surfing, kayaking, snowboarding, running, mountain biking, triathlons, and yoga as a few of my favorite things.

"On a walking safari in South Africa," I write, "I learned that I fall into the 10 percent category of women who don't run when face to face with a rare white rhino. When I was 21, I trekked to 16,000 feet in the Himalayas to bring my boyfriend a beer on his birthday." Next, I upload a photo of myself at the base of Snowbird Mountain, in Utah. Finally, to get the ball rolling, I scroll through the male profiles and send flirts to six guys who look promising.

Then I wait.