The Top Online Meat Markets

Call it calculating, unromantic and maybe even a bit unnatural, but online dating--now a $950 million industry, including membership fees, advertising revenues and Web products like chat services and virtual roses--is here to stay. Throngs of hungry hearts now cruise online dating sites for companionship.

According to Nielsen, an audience tracking firm, dating sites snared 27.5 million unique visitors in June. That's a ton of traffic--about half the amount logged by heavily taxed job-placement sites during what has been called the worst recession since the Great Depression.

Indeed, all the doom and gloom about the economy may be helping virtual love brokers. "The stress makes it clear when you're in not such a great relationship," says Greg Waldorf, chief executive of eHarmony.com. "People can feel pretty frustrated."

Dating sites don't just gin up the guest list; they do their best to get the sparks flying. Some track their members' searches and look for patterns; others poll couples to find out why some relationships worked and others didn't. Spark Networks ( LOV - news - people )--owner of a hodgepodge of niche sites like jdate.com (for Jewish singles), blacksingles.com and catholicmingle.com--hosts a popular "Rabbi of the Month" contest on jdate.com. Still other sites host member forums where the tortured masses can bleat about how to survive a break-up.

Some sites generate revenue by selling advertising, while others charge monthly subscriptions fees. (Men and women may not pay the same rate.) And like many other Web businesses, dating sites often sell different levels of service at different price points.

Forbes used Nielsen's latest unique-visitor data for June 2009 to rank the 10 most popular dating sites. (The number of unique visitors, a common Web-traffic metric, is the total number of people who visited a Web site during a particular reporting period; anyone who visited the same site more than once during the period is not counted again.)

At No. 1: eHarmony.com, with 4.25 million visitors, up 48% from the same period a year earlier. Users spent an average 24.5 minutes on the site per visit. Looking for a casual fling? Keep moving. "There's a high level of engagement around a clarity of purpose," says Waldorf. "When you subscribe to eHarmony, you're saying that you're interested in a serious relationship." Indeed, there are four stages of communication to determine your match's level of interest--and members can only see people they match with. Price: $60 a month, for both men and women.

Yahoo ( YHOO - news - people ) Personals came in at No. 2, with 4.1 million uniques, followed by Match.com, with 3.4 million. At Match, members receive their "Daily 5"--five people selected for them each day by the site's proprietary pairing technology. A "Profile Pro" will even help spruce up your online image. Membership fee: $40 a month, plus another $35 charge for the profile consulting.

Plentyoffish.com--at No. 6, boasting 2.2 million viewers, nearly double the amount a year ago--offers its brokerage services for free and looks to turn a profit selling advertising. "We've been growing so fast, I don't even know what normal is," says founder Markus Frind. Perhaps more noteworthy than the site's $10 million in annual ad revenue is the 91 minutes that an average users spends per visit. One reason for such impressive stickiness, perhaps, is that unlike other dating sites, Plentyoffish relies less on a marketing blitz than on word of mouth from satisfied customers, who in turn know the kind of people who don't have merely a passing curiosity about online dating, Frind says.

Edgy newcomer Do U Like hasn't been around a full year but has rocketed to No. 7, with 1.9 million uniques per month. Unlike other dating sites, users must post their photos--racy poses encouraged. If you like what you see, you click on the photo; if you want to see who "liked" you, check the "Mutual Sympathy" inbox. Price for such near-instant gratification: $20 a month.