A federal judge in Syracuse has cleared the way for lawyers in New York State to use pop-up ads on the Internet, but did not answer the bigger but more subtle issue of whether firms must label newsletters and e-mail messages to clients as advertising.

The decision, issued Friday, said that statewide rule changes that took effect on Feb. 1 violated the free speech of lawyers.

The ruling resulted from a lawsuit filed by Public Citizen, an advocacy group, on behalf of Alexander & Catalano, a personal-injury firm from Syracuse that had challenged limits placed on advertising by a committee of judges in New York’s appellate division.

The firm had called itself “heavy hitters” in ads and had run TV commercials depicting its lawyers as giants towering over skyscrapers, counseling space aliens about an insurance dispute and speeding to reach a client.

Gregory A. Beck of Public Citizen, who argued the case, called the images in the advertisements “silly stuff,” but added: “Attention-getting is what advertisements do.”

Judge Frederick J. Scullin Jr. of Federal District Court found that the justices who adopted the limits had “no statistical or anecdotal evidence of consumer complaints with or complaints about misleading lawyer advertising,” and had instead cited public comments by a New York Court of Appeals justice on the poor taste of billboards appearing in upstate New York.

For major firms, Judge Scullin’s ruling did not address regulations that have confused their marketing officers — whether e-mail messages had to be labeled advertisements and Web sites needed disclaimers.

“The portions that were knocked out would not have had a major impact on the large firms here in New York City. I don’t know of any big firms that use pop-up advertisements,” said David G. Keyko, a lawyer with Pillsbury Winthrop Shaw Pittman who is on a City Bar Association task force regarding the new rules.

The new rules defined advertising as “any public or private communication made on behalf of a lawyer or law firm about that law firm’s services, the primary purpose of which is for the retention of the lawyer and the law firm.”

Most firms had interpreted that to mean that e-mail messages must have a note in the subject line stating that it is “attorney advertising,” a designation that the firm said could trap the messages in spam filters.

More vexing, for them, was the need for the disclaimer “attorney advertising” that had to appear at the bottom of a firm’s Web site and on proposals seeking business.

Joseph Calve, the chief marketing officer at Proskauer Rose in New York, said large commercial firms would continue to be confused on those two points.

Mr. Keyko said that the city bar planned to issue a white paper on the issue by the end of August, and that the state bar was working on “ethical considerations” aimed at giving lawyers guidance.

The New York State attorney general’s office defended the rules, and did not return calls for comment.