It may seem passe to longtime Internet users, but online dating is growing in markets worldwide.

Since new singles come along all the time, the dating business promises to stick around. Moreover, there is a lot of room for growth for online dating and matchmaking Web sites.

"It's a highly underpenetrated market," said Thomas Enraght-Moony, chief executive of Match.com, in a February 2008 International Herald-Tribune article.

"The US has 92 million single people, and only 3 million now pay for an online dating service, and the US is the most advanced market," Mr. Enraght-Moony said. "In Japan, it's one-tenth of that penetration."

That market potential has Match and global competitors like MSN Dating and Yahoo! Personals looking for an edge. In France, Match has made membership free for women.

Online dating sites often have a problem in common with most bars: Too many men, not enough women.

MediaMark Research's "Survey of the American Consumer," released in September 2007, found that men made up slightly more than half of online dating site users.

For new online dating sites, the ratio is usually more lopsided.

"Typically," Mr. Enraght-Moony said, "the day you open, it's 90% men, so you have to build a site that attracts women."

Match said that 55% of its new users in France are women, compared with 40% in most other markets.

About half of single UK men and women said they had used an online dating site in the past 12 months in 2007, up from the roughly one-half of men and one-third of women who said so in 2005, according to PARSHIP's "Singles Survey 2008: Media Summary UK" report, conducted by Innofact.

Worldwide, 97 million people visited Web sites devoted to matchmaking in December, according to comScore data cited in the Herald-Tribune article. That was down 10% from a year earlier.

That is probably not because of dating on social networks.

Consumers can date online for free on social networks, but those same consumers were unlikely to have paid for dating site subscriptions. Online dating site users are looking for a pool of other people who are serious about dating, and pay for access to that pool.

The social network pool may be larger and free to use, but not everyone is there to swim.

The eMarketer UK Internet Users and Usage report will be published this month. Click here to be notified when it is released.