A Pittsburgh lawyer is suing the creator of a Web site and several people who posted messages there claiming he has a sexually transmitted disease, complains about paying his child support and is unfaithful.

Todd J. Hollis filed the lawsuit yesterday in Allegheny County Common Pleas Court against Tasha C. Joseph, 33, of Miami, owner and operator of www.dontdatehimgirl.com, because two local women and other anonymous subscribers to the site posted statements about him that he claims are defamatory.

Ms. Joseph, a former columnist for The Miami Herald, said she started the site in 2005 to allow women whose husbands, boyfriends or fiances had cheated on them an outlet to warn other women by posting the men's pictures and profiles into a searchable database. She writes on her site that "women have a new cost-effective weapon in the war on cheating men!"

Those who visit the site must sign up to become members to view the postings, but all that is required for membership is a valid e-mail address.

The lawsuit filed on behalf of Mr. Hollis, 38, of East Liberty, said Ms. Joseph has "conspired with disingenuous people whose only agenda is to attack the character of those individuals who have been identified on her site." The suit says there are no protocols to ensure statements on the site are valid or truthful. Mr. Hollis, who has practiced criminal law for 12 years, claims statements posted on the site, which appear to be by different people, have affected his practice and family life.

The complaint says items on the site characterize him as a shabbily dressed and diseased womanizer.

A family member called Mr. Hollis shortly after reading a posting and, after looking at the site for himself, Mr. Hollis called the offices of dontdatehimgirl.com, seeking to have his picture removed and the posting retracted. He claims the operators of the site refused, although he learned later that a woman who posted the item voluntarily removed the message 36 hours after it had been posted.

The site has a rebuttal policy for men wanting to challenge postings about themselves. "Send us an e-mail, tell us what happened. We'll post it next to your profile," says a notice flanking a photo of a man tearing his hair.

Ms. Joseph said Mr. Hollis was told he could post such a rebuttal. Mr. Hollis said he refused because he did not want to become involved in name-calling.

More than 6,000 people have viewed profiles of Mr. Hollis on dontdatehimgirl.com, according to a tally on the site.

Lawyers for Ms. Joseph said her site and others are protected by a federal statute for host sites that offer users access to search engines and message boards. They said someone who operates a Web site where other people post messages is not liable for the message content under the 1996 Communications Decency Act. Ms. Joseph said this will be the first lawsuit against her Web site, though she says she has been threatened with suits a number of times.

"This is no different than the proverbial coffee shop where people go and chitchat," said Lida Rodriguez-Taseff, one of the lawyers representing Ms. Joseph. "You would never think of holding the coffee shop owner liable because other people went in and defamed other people."

Ms. Joseph said it was not the site's responsibility to notify people who are described on the message boards.

The site receives more than 600,000 hits a day and has 525,000 registered users.

"It is like the FBI most wanted criminal database online," said Ms. Joseph. "We thought it would be interesting to apply this concept to the cheating, lying men of the world and save women the heartache."

Ms. Joseph said her small office in Miami receives hundreds of phone calls from angry men wanting to get themselves removed from her site.

Some of the men take advantage of the rebuttal policy and others do not.

There is even a Web site created to counter Ms. Joseph's: www.classaction-dontdatehimgirl.com provides a forum for disgruntled subjects of dontdatehimgirl.com.