Badoo, the wildly popular social network where random strangers accost you for no reason.

Since the dawn of the online era, we have found ways to socialize in virtual space. BBS. IRC. The briefly ascendant Chatroulette. Message boards devoted to chatter about Boston sports franchises and/or the music of Stephen Malkmus (I’m just generalizing here).

The latest buzz phrase in the world of online kibbitzing is "social discovery." A classic social networking site like Facebook, the argument goes, is best suited for interacting with folks you've already met in real life. Social discovery sites are designed to help you find and meet new people.

Badoo is perhaps the most successful social discovery site on earth. Until the massive ad campaign it launched this spring in New York City—plastering subway cars with photos of young, attractive New Yorkers, all putatively clamoring to chat with you online—I had never heard of it. When I polled friends to see if they were familiar with Badoo, most confused it with Baidu, the Google of China. But it turns out that Badoo has registered 150 million users worldwide, is available in 40 languages, and clocks more than 7 billion page views each month.

Intrigued by this little-known social behemoth, I registered a profile and began to wander through the site. My first sensations: Chaos. Confusion. A powerful impulse to flee and hide. The Badoo layout is a riot of colors and clickable buttons. A miasma of thumbnail photos showing men in sideways baseball hats and women in clingy halter tops.

Within moments of posting a single, boring photo of myself, and listing my interests as racket sports and sushi, strangers began to initiate chats with me. Stacy, of Beaver Dam, Wis., wrote, “Hi.” So I clicked on her face. She listed among her interests short-shorts, Skittles, Swarovski, and chicken. I wasn’t quite sure what we were supposed to talk about. Imagine an unknown woman from Wisconsin—perhaps wearing crystal-encrusted short-shorts, munching on Skittles, etc.—rushing up to you on the sidewalk and expectantly waving. How best to respond?

You might well interpret the act as flirtation. And, after further exploration of Badoo, I concluded that flirtation is the site’s real purpose. Most profiles I clicked on declared romantic intentions: “Wants to go on a date with a guy, 22-37” or some such. This is a hookup site, I realized. My suspicion was bolstered by the fact that, like Grindr (the app for gay dudes in search of instant love), Badoo tells you people’s proximity—presumably so you can find someone within .3 miles who lists as an interest making out with people I’ve just met.

In fact, it’s tempting to declare Badoo a Grindr for straight people—and some have. But not so fast, says Jessica Powell, Badoo’s chief marketing officer. On the phone from London, Badoo’s global headquarters, Powell assured me that Badoo is just a forum for making new friends and chatting, and that dating is merely a secondary result of that process. She likens it to being at a bar in a South American city, where people are apt to casually approach one another other and say hi with no immediate ulterior motive. (When I was at Burning Man last year, a Brazilian fellow told me he loves the festival because he gets to see “Americans acting like Brazilians—anyone can just walk up and say hello to anyone else.”) Powell theorizes that this culturally specific preference for no-pressure chatting is why Badoo has spread quickly in South America and Spain and has made some of its strongest strides in the United States with our Spanish-speaking population.

But will this free-for-all format catch on with a broader American audience? Logging on to Badoo left me puzzled—I wasn’t sure where to begin. This isn’t a themed message board site where people with niche interests can gather to chat about crossword construction, say, or how to achieve perfect forearm pronation when swinging a squash racket (again, just generalizing). There’s no particular reason or basis for most interactions, beyond an intriguing thumbnail shot.

And unlike dating sites, Badoo has no algorithm. No computer program whirs on your behalf, in search of your ideal match. You’re just thrown into the scrum, much as you would be at a club or a big party. Though, to be fair, the act of rejection is more distanced online: Women can shut down to an unwanted Badoo advance by simply clicking away from a chat invite, while at a bar they cannot physically evaporate at will, try as they might.

Interestingly, Badoo doesn’t sell display ads. Which is sort of amazing, given the volume of traffic it boasts. Instead, Badoo makes its money—it is projecting $150 million in annual revenue over the next year—through micropayments. Users can pay $1.99 to boost their visibility on the site, briefly promoting their thumbnail picture to the top of the welcome page, or elevating their ranking in search results. The strategy makes sense for Badoo, whose users often log in from their phones: Display ads don’t generate as much revenue on mobile platforms, in part because the phone’s screen size is so limited. Facebook has been bumping up against this very problem. Micropayments are one solution.