Zippo is a landmark opinion regarding personal jurisdiction for courts deciding Internet-oriented disputes, and it is one of the most frequently cited Internet law precedents.

Zippo.com was an unaffiliated California corporation that operated an Internet website offering access to USENET newsgroups.

Under the sliding scale, "the likelihood that personal jurisdiction can be constitutionally exercised is directly proportionate to the nature and quality of the commercial activity that an entity conducts over the Internet.

At the "weak" end of the scale is a passive website that merely posts text with no opportunity for interactivity or business transactions.

[3] Thus, the District Court denied Zippo.com's motion to dismiss the suit, enabling a full trial for the manufacturing company's trademark claim.

[5][6][7][8][9] However, some other courts have rejected that test, criticizing the matter of casual Internet usage by citizens as a factor in determining jurisdiction.