THE GIST

- Online is one of the most common places that people now meet romantic partners.

- The Internet gives people access to far more potential partners than they are likely to meet in the real world.

- Matchmaking algorithms likely don't work.

In just 20 years, the Internet has become one of the most common places to meet romantic partners -- a close second only to getting introductions through friends, found an exhaustive new review of research into the science behind the online relationship industry.

By far the best service that online dating sites offer, the study found, is access to other single people who are looking for love. On the other hand, there is no good evidence to support the "science-based" algorithms that supposedly find the perfect match for you.

Among other limitations, user profiles also offer an incomplete sense of a whole person. And when daters are presented with too many people to choose from, they often get overwhelmed and give up.

By taking a comprehensive look at the exploding world of online dating -- with its many strengths and weaknesses -- the study suggests ways that singles might make the most of online dating sites. The findings also point out ways that the industry might serve its clients better.

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"The fact that online dating exists is a boon for singles, and it is a great addition to the way singles can meet potential partners," said Eli Finkel, a social psychologist at Northwestern University in Chicago. "But the industry makes a number of mistakes."

From Cupid to matchmakers to nosy grandmothers, intermediaries have been meddling in love since long before the beginnings of the Internet. Finkel and colleagues wondered whether online dating was simply a newer form of an ancient tendency to get people hooked up, or if the industry represented a quantum leap.

That proved to be a hard question to answer. After all, there are no studies that randomly assign people to one kind of dating or another and then test which works best.

Meanwhile, the algorithms that companies use to suggest potential dates to their clients are carefully guarded industry secrets. So, even though some companies claim that their methods are scientifically proven to spark romance, independent researchers do not have access to the formulas for testing.

Looking for love? The Internet has become one of the most common places to meet romantic partners. iStockPhoto

In fact, given the kind of data dating sites have to work with, it is hard to imagine that any matching algorithms could possibly work, Finkel said. His research on speed dating has shown that people can tell almost instantaneously if there's an attraction when they meet in person. The same is not true online.

"Despite hundreds of millions of dollars spent on hugely expensive advertising campaigns claiming to use psychology or relationship science, they haven't produced any evidence that these work that any scientists would find compelling," Finkel said.

"People aren't two-dimensional profiles. You can figure out in a matter of minutes or even seconds if there's a spark. Fifty million hours of reading profiles online isn't going to tell you that."

Excessive profile-browsing can also be detrimental because of the problem that people tend to run into when they have too many choices. Plenty of psychological research shows that people are more likely to stop and sample something like jam if there are many flavors to pick from. But shoppers are more likely to buy if there are only a few options. The same is likely true for potential romantic partners: Having too many choices can be paralyzing.

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To make the most of your online dating experience, researchers recommend spending as little time as possible browsing and more time setting up short meetings, which can reveal quickly whether a match was made in heaven or not. Also useful are apps that alert people when potential dates are nearby -- offering even more opportunities to test for connections.

"These are dates you otherwise wouldn't have had," Finkel said. "Each new person you meet online is chance for a spark that is worth exploring."

Eventually, sites might get better at facilitating relationships. Scripts that guided people through their first meeting could help enhance attraction, said Arthur Aron, a social neuroscientist at Stony Brook University in New York. Many daters could also benefit from training in communication skills or profile-writing. Some of the newer technologies might prove to be more promising, as well. There are sites, for example, that use surveys to gauge hormonal compatibility or DNA tests to match through genetics.

For now, despite the significant limitations, online dating programs can be valuable services for people on the prowl. Twenty years ago, just 1 percent of people in successful relationships had met online, Finkel said. As of 2009, 22 percent of heterosexual couples surveyed in one study had met through the Internet. More than 60 percent of same-sex couples now meet via their computers.

By 2005, nearly 40 percent of single Internet users were dating online, and that number is most likely higher today.

"This is a good thing and it helps people meet who otherwise would have to go to bars," Aron said. "People do meet through friends, but it's difficult and that's probably the single biggest virtue of online dating and probably why it's so popular. The riskiness of asking someone for a date is pretty hard for a lot of people. This helps get past that."