1. A unique browser (as identified by cookie) that visits (accesses) a website. 2. A single email address. See also visit, visitor.

An individual visitor to a Web site. Tracking unique users is important in ascertaining the success of a given Web site because it indicates how many different visitors access the site, as opposed to the number of hits—visits by the same or different individuals—the site receives. Also called: unique visitor.

an individual visitor to Salon's network

A unique visitor your Web site. You can determine unique users by assigning a different cookie to each visitor, then checking the cookie during each visit to your site.