By BUCK WOLF

July 12, 2005 — When you're dating on the Internet, a broken heart may be the least of your worries. Luckily, technology is here to help you distinguish potential soulmates from future cellmates.

"I do not shop online except when it comes to men," says Sonja, a 38-year-old health food store owner featured on "Hooking Up," a five-part documentary series premiering July 14 at 9 p.m. ET. The series will follow the yearlong travails of 11 stylish Manhattan women looking for love online.

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Some 40 million Americans — nearly one out of every two unmarried people — have tried Internet dating in recent years, turning it into a $1 billion business.

But for all the promises of easy-to-find romance, online dating is a minefield of instant rejection, as well as cads of both genders who hire pros to write their personal statements and retouch their pictures, or lie about their age, height, weight, education, profession and marital status.

In the first "Hooking Up," we'll see a guy in his mid-40s who apparently used a vintage photo to pass himself off as a 30-something. We'll also meet a gal who rejects a suitor based largely on the ice cream he orders — vanilla with no sprinkles.

Modern lovers can expect to run into even more serious transgressions. In a recent survey, Jupiter Research found that 12 percent of people who have registered with an online dating service are married.

Some dating services — like True.com — perform criminal background checks and warn that "married people will be prosecuted." Another new site — eLove.com — requires new members undergo face-to-face screenings at which company officials verify that the pictures you're posting are actually of you.

But cheaters are more than welcome at AshleyMadison.com, a Web site for married adults "with unmet needs" that boasts the slogan "When Monogamy Meets Monotony."

About 200,000 people have registered at the Toronto-based Web site. One reason Ashley Madison has such an unassuming name — and not something like ExtraMaritalThrills.com — is so it won't raise red flags when your spouse sees your credit card bill.

Even cheaters have their rules. Ashley Madison newbies are encouraged to get specific about the extramarital pleasure they're seeking. "Swingers" should distinguish themselves from those seeking a "secondary relationship" — a long-term romance that's not necessarily sexual.

A "tertiary relationship" is a polite way to refer to a one-night stand. And be warned: Some married daters expect you not to cheat on your mistress with another mistress — a concept known as "poly fidelity."

Perhaps dating has always been risky. But our increasingly complicated high-tech society seems to simultaneously make it easier to meet other people, yet harder to wade through them to the love of your life.