Anonymous commenting may have just gotten a little less anonymous.

With the help of a subpoena issued six months ago, attorneys for two Yale Law School students have succeeded in unmasking several anonymous users of the Web forum AutoAdmit whom the women are suing for defamation.

Some of the defendants will finally be named when the students soon file an amended complaint, said their attorney, Stanford Law Professor Mark Lemley, who declined to comment further.

While this development does not break any new legal ground, several experts interviewed said, it is one of the few, and certainly one of the highest-profile, examples of defamation lawsuits that have successfully pierced the veil of online anonymity.

In 2005, sexually explicit and derogatory posts targeting three female Yale Law students appeared on AutoAdmit, an online community where law students can discuss law-school admissions and law-firm life. Two of the students, who remain unnamed in the suit, filed against the 39 authors of the allegedly defamatory posts.

Since a federal judge in New Haven granted subpoenas of Internet service providers last January, several of those comments have been successfully traced through their electronic footprints.

One of those authors was “AK47,” who, in 2007, posted that women with one of the Yale Law students’ names “should be raped” and said that he and that student were “gay lovers.”

John Williams, a court-appointed lawyer who represented AK-47, whom he has never met and whose identity he does not know, said he was disappointed by the judge’s decision to sustain the subpoena, which he said went beyond where any other court has gone.

“Free speech takes another hit,” he said.

The discovery of AK-47’s identity still follows “well-worn grooves” and has not yet ventured into uncharted legal territory, said First Amendment lawyer Marc Randazza, who is no longer involved in the case but formerly represented an AutoAdmit administrator, Anthony Ciolli, who was initially sued as well.

Courts have long recognized that subpoenas may be available to identify anonymous commenters if litigants can demonstrate a plausible case for defamation and are not simply trying to intimidate critics, said Eugene Volokh, a law professor at the University of California, Los Angeles.

Volokh said that while subpoenaing ISPs to identify commenters under certain circumstances is settled law, he is not sure whether the tactic has ever been successfully deployed before.

But even if this case does not set new precedent, he said, its publicity may serve to discourage some speech by dramatizing the boundaries of anonymity.

“It might remind some potential would-be defamers that their anonymity may not be secure,” Volokh said.

Anonymous speech is usually constitutionally protected, but defamation and threats are not, Volokh said. In order to issue a subpoena, litigants need to show that they have valid grounds and a serious claim, Randazza said.

“If you’re doing right, the First Amendment will protect you,” Randazza said. “If you’re doing wrong, it won’t.”

Even after this latest stride forward, the students’ suit has become increasingly messy as it wears on, heaping up a thicket of countermotions and time extensions. The two Yale Law students and their attorneys have also been countersued by Ciolli, who is alleging wrongful prosecution.

The two students did not reply to requests for comment. David Rosen, a New Haven lawyer who is also representing them, did not return a phone call.