Court of California, the Court unanimously agreed that this rule was still effective, but split as to the rationale. Justice Scalia wrote for four justices who felt that the rule should apply simply because it was a continuation of a longstanding tradition. Justice Brennan wrote for four justices who felt that the rule should apply because the party was purposefully availing himself of the benefits of being in the state at that time, and that the rule was fair under modern standards because it was well known, therefore putting defendants on notice of their susceptibility to suit in a state if physically present. The ninth vote, by Justice Stevens, agreed that jurisdiction was proper, but did not endorse either Scalia's or Brennan's test. Commercial activities Merely placing products in the "stream of commerce" is insufficient to provide minimum contacts with the states where the products end up. The defendant must make an effort to market in the forum state or otherwise purposefully avail himself of the resources of that state. However, since only four of the nine Supreme Court Justices joined the opinion that required a defendant to do more than place his products in a "stream of commerce," some lower courts still rule that doing so is adequate for a court to exercise personal jurisdiction. Claims arising from the tort of defamation are treated by a different standard.<ref>See Keeton v. Hustler Magazine, Inc., , and Calder v. Jones, .</ref> Internet activities Courts have struggled with the Internet as a source of minimum contacts. Although not determinately established by the Supreme Court, many courts use the Zippo test, which examines the kind of use to which a defendant's website is being put. Under this test, websites are divided into three categories: passive websites, which merely provide information, will almost never provide sufficient contacts for jurisdiction. Such a website will only provide a basis for jurisdiction if the website itself constitutes an intentional tort such as slander or defamation, and if it is directed at the jurisdiction in question; interactive websites, which permit the exchange of information between website owner and visitors, may be enough for jurisdiction, depending on the website's level of interactivity and commerciality, and the number of contacts which the website owner has developed with the forum due to the presence of the website; commercial websites which clearly do a substantial volume of business over the Internet, and