After looking for love on the Internet and failing to find it, frustrated lonely hearts are heading to court, accusing online dating sites of engaging in deceptive practices.

A recent lawsuit against Match.com charged the matchmaking service with sending a female employee out on a date with a male subscriber as "date bait" to keep him signed up. Another lawsuit against a personals service offered by Yahoo Inc. accused the Internet portal giant of creating fake profiles to entice subscribers.

Match.com denied the allegations and obtained an affidavit from the woman in question, who declared she never worked for the company. Yahoo refused to comment.

The federal fraud lawsuits, which seek class-action status, have roiled the lucrative online dating industry. A 2004 report by Jupiter Research estimated the U.S. Internet personals market had revenues of $473 million that year — the largest moneymaker for online content.

In the Match.com lawsuit, filed Nov. 10 in U.S. District Court in Los Angeles, plaintiff Matthew Evans made the "date bait" allegation against Autumn Marzec. He also accused the site of using fake profiles and sham e-mail "winks" from potential matches to keep him subscribed. Match.com, which claims more than 15 million members, offers a basic subscription for $29.99 a month.

Marzec said in a signed affidavit that she has never been employed by Match.com or its parent company, InterActive Corp., and has not worked for them as a contractor. On Monday, Match.com demanded that Evans dismiss the lawsuit, which it called a "totally baseless attack."

Evans' attorney, Mike Arias, said Wednesday he has no intention of dropping the suit.

The lawsuit against Yahoo was filed in October in U.S. District Court in San Jose by plaintiff Robert Anthony of Broward County, Fla.

The suit says Yahoo posts fake profiles on its personals site "to generate interest, public trust and give the site a much more attractive and functional appearance." Yahoo charges $19.95 a month for a dating service and $34.95 a month for a service geared for people looking for more serious relationships.

Anthony alleged that Yahoo also sent him fake "new match" messages when his monthly subscription was up for renewal. After months of failing to meet a potential match, he became suspicious and discovered the same picture of a woman being posted for different cities under different names, according to his attorney, Randy Rosenblum.

"He wants to expose what he believes to be illegitimate conduct on the part of Yahoo and stop it from happening," Rosenblum said. "Because people are signing up for a service and are paying for it and they are not getting what they are paying for. They are being misled into thinking there are people out there who are interested."

Trish McDermott, chief matchmaker at Engage.com and a member of Match.com's startup team, said she never saw any type of consumer fraud during her decade at Match.com

"The true enticement of these services are the real people who like you for who you are," McDermott said.

But she added that the majority of personals sites, including Yahoo and Match.com, employ a business model she believes fails consumers.

It's not clear who is a member and who isn't in the pay-to-respond model, in which a user must join a service to respond to an e-mail sent by a potential match but cannot post a profile, McDermott said.

If someone e-mails 100 people and gets only one response, he or she could conclude that most of the profiles are fake when they actually show non-subscribers who can't respond to e-mail, she said.

Jupiter Research found in a consumer survey that 35 percent of online dating users at three major sites — Match.com, Yahoo Personals and Spark Networks — were dissatisfied.

"Their expectation is to find an authentic person and to fall madly and truly in love, yet the experience can be very demoralizing for these people," McDermott said.