"Marriage is not the most common unit of measure of a company's success. But that's exactly how eHarmony.com Inc., an online matching service that stresses its formula for long-lasting relationships, assesses its business value, staking claims on the number of marriages its service would generate in the future. The profitable firm convinced investors, Sequoia Capital and Technology Crossover Ventures among them, to contribute nearly $110 million in one of the largest venture capital rounds of the year. It needs the money to support its large customer call center, marketing efforts and growing team. As one of its competitors, Matchnet Inc., which runs dating Web sites AmericanSingles.com and Jdate.com, said in its IPO filing that it pulled later this year, "We operate in a highly competitive environment with minimal barriers to entry."

Though specific financial figures for eHarmony aren't disclosed, a look at Matchnet may offer some insight. The company, which charges each user up to $34.95 per month, doubled its 2003 revenue in 2004, bringing in about $31 million. Of that, it spent $17 million on marketing, $2 million on customer service and $3 million on technical support, winding up at $7 million in the red.

The founders of eHarmony, Neil Clark Warren and Greg Forgatch, stress less the romantics and more the science. A patent they filed this summer describes a method and system that attempts to "bring together two or more people that the matching service believes may have a successful relationship." The complicated formula involves such statistical methods as factor analysis, multiple linear regression and correlation analysis, as well as the deriving of variables such as the individual satisfaction index. The index can be used to classify individuals into unlikely, average and good categories. Those falling in the unfortunate "unlikely" category are unlikely to be happy in any relationship. The matching service may choose not to match people who fall within the unlikely classification, claims the patent, boosting the success rate of its matches. The company, which said its revenue has more than doubled in the past year, has 5.8 million users and also claims that the matching model eliminates 99.7% of "people who are not for you."