FORTUNE MAGAZINE - Feb 14 - There are thousands of sites out there, many with an incredible degree of specificity in their target audience. The personals sites for The Onion and Salon are both powered by a service called FastCupid. That company is a property of FriendFinder Network. FriendFinder Networks, formerly called Penthouse Media Group, operates ~40K sites. FriendFinder does not mix together all the profiles of all its branded sites. Because people from BigChurch.com for Christian singles for example, may not get along with those from another, say, Bondage.com. Many established online dating operators eschew the practice altogether, but it's fairly common, particularly in the U.K. where it's standard practice. Today, four companies control 77% of the $1.22 billion online dating market, according to research from IBISWorld. IAC controls 41% of the market, eHarmony is next, with 23.5%, in third place is Zoosk at 7.7%, followed by Spark Networks at 4.9%. Despite the competitive advantage conferred by niche markets, big data-driven dating clearinghouses may be the way of the future for much of the online dating industry. "Strategically, bigger is best," says Brooks, industry analyst and editor of Online Personals Watch. "If you consider what would be the perfect model for an Internet dating site, in theory it would have all the people in the world who are single on it, and you could find your perfect match within a day's work." A single major U.S. service that controls more than 50% of market share is "inevitable," Brooks says. In theory at least, a bigger pool means more happy matches, even if they're from unlikely sources. Data confirms: "It's kind of a waste of time anyway asking people what they want anyway," Brooks says. "Because they don't really know."