Online dating is hugely popular, so we took a look at how some of the most popular sites work.

There's no doubt online dating sites are big business. Unlike personal ads, which were once seen as embarrassing, finding love on the web has become one of the most popular online activities. According to ComScore, online dating sites drew 22.1 million unique visitors in December last year.

And unlike many social-networking sites such as Facebook and MySpace, they actually make money - the top sites bring in hundreds of millions per year, mostly in subscription fees.

These online dating services run on a curious mix of technology, science (some say pseudoscience), alchemy and marketing. Under the covers, they combine large databases with business intelligence, psychological profiling, matching algorithms and a variety of communications technologies to match up lonely singles - and to convert one-time visitors into paying monthly subscribers.

Security is one big challenge for e-dating services, which can attract peadophiles, sexual predators, scammers, spammers and plain old liars - most notably, people who say they're single when in fact they're married. And sticky questions have yet to be answered over what rights such sites have to your personal information - how they use it to market other services to you, if and how they share it with advertisers, and how long they store it after you've moved on.

Finally, there's the biggest question of all - do these tech-driven, algorithm-heavy sites work any better to help people find true love than the local bar or chance encounter in the street?

The business model behind online dating

A well-oiled internet dating machine can generate well in excess of $200m a year in a market that's expected to top $1.049bn in 2009 - only gaming and digital music sites generate higher revenues - and is expected to grow at a rate of 10 percent annually, according to Forrester Research.

Most online dating sites generate the bulk of that revenue from subscriptions, although free, advertising-supported sites are starting to gain some ground.

In fact, Plenty of Fish, a free service, was the second-most-visited online dating site last year, according to website traffic monitoring service Hitwise.

Visit Broadband Advisor for the latest internet news, reviews, tips & tricks - and to take advantage of PC Advisor's unique, independent Broadband Speed Tester

NEXT PAGE: How dating sites succeed

  1. Can you really find the love or your life online?
  2. How dating sites succeed
  3. Sophisticated data centres
  4. Online dating site visitors
  5. From 'just looking' to 'paying customer'
  6. Make a high-quality connection
  7. Weeding out cheats, scammers and married guys
  8. Do online dating sites work?