KRISTEN GIESSLER HAD JUST LEFT a party downtown at the Boston Society of Architects. It was 11 p.m. She had had a few beers and wanted to wait a while before driving home. So in a move as natural as applying lip gloss, she clicked on her iPhone and logged onto the dating app OkCupid Locals.

Using the GPS coordinates tracked by her smartphone, the app pinpointed Giessler’s exact location — 290 Congress Street — and then displayed a list of single men within several blocks who were also on their phones and looking to meet someone right that minute. OkCupid Locals is meant to follow you wherever you go and find you matches along the way. And these guys seemed promising. She’d never seen them while looking at OkCupid profiles from her Ashland condo.

First, the 33-year-old Giessler clicked on the profile of a guy looking for someone to sing karaoke with, but he didn’t have a college degree, a deal breaker for her. Guy number two looked cute enough, but he was a Republican. “No way,” she said, laughing. The last guy was looking to see a movie and shared her interest in sailing. She messaged him: “Hi there : )” and he ping-ponged a message right back. Within minutes, standing several blocks away from each other, they were chatting about a possible date.

It was so immediate, it was intoxicating. In the past, Giessler had sat at home in front of her computer, sifting through an endless stream of profiles to figure out who was worth messaging. “Oh, the messaging,” she sighs. “It could take weeks before you even get a date, or you just realize you’ve been talking to someone who just wants to write and write. There’s a lot of that.” She uses location-based mobile dating apps for one reason: They’re efficient. In an age when we live and breathe by our cellphones and expect our every whim to be satisfied right that second, it’s only natural that online dating should migrate to mobile. Says Giessler, “It cuts to the chase and helps you meet people faster.” (Although she and bachelor number three never did meet up.)

Giessler planned to use the app again the next weekend. “I could see myself getting dressed up and spending my evening reading my next book club novel in some Starbucks downtown or in Cambridge and seeing what happens — either by responding to someone’s broadcast or making my own,” she says.

Whether you live in Davis Square in Somerville and head to the North End for dinner or have a place in Andover and travel to London on business, a big advantage of location-based dating is the ability to pull from a completely different pool of singles, a fresh sea of faces, depending on where you are. In theory, this gives you a greater chance of meeting someone. Forget the romance algorithms of online dating sites that promise they’ll find you a perfect match based on a list of personality traits. Many of these newer apps are designed to show you who else may be out there, perhaps waiting in line ahead of you at the Cambridge Whole Foods after work. And in doing so, some singles say, they’re bringing a layer of serendipity — and, dare I say, romance — back into online matchmaking. Not only can you find out who else is single in the Public Garden, some apps will also reveal how each person wants to spend his or her afternoon — and then you can propose joining in. How tantalizing is the thought that the person you’re destined to meet might actually be right there in front of you?

“With these apps, the security line at Logan can become a round of speed dating,” says Alex Harrington, CEO of MeetMoi, a mobile dating app that sends users alerts when other singles are nearby.

By tapping into the power of smartphones, location-based dating could revolutionize the way we meet people over the next few years. But if it’s so great, why are so many Boston singles, particularly women, wary of using it?

***

In recent years, online matchmaking has become a billion-dollar business, with one study showing 30 percent of the adult population using some form of online dating. While many report high numbers of young people on their online dating sites, baby boomers, as Time reported in 2010, are the fastest-growing age group looking for love online.