In its first major ruling on privacy and defamation in cyberspace, the Court of Appeals on Thursday held that an Internet Service Provider (ISP) is merely a conduit for information, as opposed to a publisher, and consequently is no more responsible than a telephone company for defamatory materials transmitted over its lines.

The Court unanimously upheld an Appellate Division, Second Department, decision that dismissed a defamation lawsuit brought against Prodigy Services Co., by the father of a Boy Scout whose identity was usurped by an unknown imposter. The imposter posted vulgar messages in the boy’s name on an electronic bulletin board and e-mailed abusive, threatening and sexually explicit messages, also in the name of the boy, to the local scoutmaster.