In a case reminiscent of the trouble Craigslist almost got into, a federal district judge has ruled that the Web site Roommates.com can be held liable for violations of the Fair Housing Act because it requires users to disclose their gender, sexual orientation and family status, and allows them to use the same information about others to facilitate roommate matches. Roommates.com says it will appeal the decision.

The Craigslist case was settled in March of this year when a federal court ruled that the company was not liable for discriminatory ads posted on the site under the Communications Decency Act and was merely a “messenger.”

Roommates.com made a similar argument and a trial court in fact ruled that the site was immune from potentially unlawful conduct of its users under the Communications Decency Act. But the decision was partially overturned on appeal, and the company must now prove that it is not liable for violations of the Fair Housing Act and similar state and local laws.

The lawsuit is not a new one: It was filed nearly five years ago by the Fair Housing Council of San Fernando Valley and the Fair Housing Council of San Diego.

Roommates.com has argued that the law, which was enacted in 1968, was not intended to “legislate the selection of roommates.” And, while the Ninth Circuit Court of Appeals found that Roommates.com was not liable for content added by users into the comments box, the drop down menus themselves – asking for information like sexual orientation (note: a required field) – were more than a “passive transmitter” of information.

The Electronic Frontier Foundation, not surprisingly, supports Roommates.com, arguing that if the lawsuit is upheld, it would affect the ability to tag content on social media sites from YouTube to Flickr.

If the decision is not overturned on appeal, the councils in San Diego and California’s San Fernando Valley have already agreed to accept $175,000 to settle their damage claims against Roommates.com.

As of today, Roommates.com has a total of 112,756 roommates available. The site receives some 50,000 visits and 1,000,000 page views per day.