The total number of different users, or different computer terminals which have visited a Web site. This is measured using advanced tracking technology or user registration. Source: Lazworld

Unique users refers the the number of distinct individuals, as determined by IP address, user login, cookie, or some combination thereof, who visit a web site or view a banner ad. Most ad networks favor sites which generate a large number of unique impressions over sites whose users view large numbers of pages. A typical ad network will often not s [..]

The number of individual users, as identified by unique computer addresses, that visit a web site.

The number of individual users, as identified by unique computer addresses, that visit a web site.

A specific mobile subscriber. Every mobile subscriber has some sort of alpha and/or numeric code that is sent with each advertisement request. These ‘unique identifiers’ are used to determine how many unique visitors view each ad.

The number of different users who access a Web site or page during a given period. To measure this, Web sites often employ a user registration system.

The number of different users who view a website within a certain time period. This is different from the number of hits, since each user could visit more than once. To identify unique users, a user r [..]