By Mira Schwirtz

Mobile dating—the latest high-tech dating trend—means romance is now literally in the air, traveling wirelessly, thanks to a slew of new mobile startups and established players rushing to pluck dollars out of the ether. Indeed, revenues from mobile dating services are expected to top $215 million by 2009, according to research firm Frost & Sullivan.

Startups such as MeetMoi and Crush or Flush are at the forefront of the trend, hawking wireless services that help folks find impromptu dates in their neighborhoods, while social networking giants like Match.com or Facebook have launched similar services or scaled down their sites for cell phones. “There will be a massive paradigm shift in how people date, going from PC to mobile because their interest isn’t only what they have in common with someone—space and time are going to be more important,” says Andrew Weinreich, founder of New York City-based MeetMoi, which is backed by Acadia Woods Partners and other investors.

MeetMoi, which launched in January, built its business expressly for the cell phone. The service, which can be accessed on any mobile network, lets users scroll through profiles to pick dates. But MeetMoi’s biggest selling point is a location-based algorithm that can search for dates in a user’s immediate area so a meeting can be set up right away. Other services like Match.com’s matchMobile, which rolled out last month, let users receive cell phone text alerts about potential dates. “Some of the simpler forms [of mobile dating] are extensions of the online service, offering alerts or texting,” says Jupitermedia wireless analyst Julie Ask. “But the more sophisticated ones are going to offer users possibilities in their area.”

Location-based services don’t work for everyone, Ms. Ask points out, given that the chances of finding someone who meets a user’s criteria in a specific location are slim unless a company has millions of members in its database, like Match.com, or has marketed itself in a dense urban area, like MeetMoi in New York City.

The demographic target for most mobile dating services is 18- to 30-year-olds, with Crush or Flush skewing even younger. Fees range from $0.99 for 10 text messages (MeetMoi) to $4.99 a month for unlimited email (matchMobile).

To appeal to teenagers, Bellevue, Washington-based Crush or Flush lets users winnow out their “crushes” as they scroll through other users’ photos. The photos they don’t like can be deleted or “flushed.” Average use of the service is about 20 minutes twice a week, says Crush or Flush Marketing Director Josh Levine. The service, which says it has 250,000 active members, plans to charge for subscriptions and other services, and generate additional revenues from ads. Crush or Flush has backing from Lightspeed Venture Partners and Frazier Technology Ventures.

Los Angeles-based Helio, a joint venture between South Korea’s SK Telecom and Atlanta-based EarthLink, has partnered with MySpace to link the site’s users wirelessly. Helio also offers a GPS-based service that transmits a user’s location to friends. More than half of its 100,000-plus subscribers use the service, says Helio spokesman Rick Heineman. Loopt, based in Mountain View, California, and backed by Sequoia Capital and New Enterprise Associates, offers a similar service.

But giving mobile daters access to others through GPS navigation opens up the possibility of harassment and makes carriers leery about adding the feature. “There are a lot of privacy and safety issues the industry has to sort through,” says Mr. Levine, adding that Crush or Flush will only show a user’s location to people listed as trusted friends. MeetMoi says it doesn’t reveal the exact location of potential dates.

Ultimately, some industry watchers say the success of mobile dating will depend on cell phone technology. Many phones are too slow and too small to handle rich media content. In contrast, Mark Brooks, publisher of Social Networking Watch, says devices made specifically for data transmission like the iPhone or Blackberry will become more popular with everyone, including the mobile lovelorn. “A lot of this is going to be device-driven,” he says.