From U to Z

UMTS(Universal Mobile Telecommunications System)

Broadband, packet-based transmission of text, digitized voice, video, and multimedia at data rates up to and possibly higher than 2 megabits per second, offering a set of services to mobile computer and phone users no matter where they are located in the world.

Unduplicated audience

The number of unique individuals exposed to a specified domain, page or ad in a specified time period.

Unique user

Unique individual or browser which has either accessed a site(see unique visitor)or which has been served unique content and/or ads such as e-mail, newsletters, interstitials and pop-under ads. Unique users can be identified by user registration or cookies. Reported unique users should filter out robots. See for ad campaign measurement guidelines.

Unique visitor

A unique user who accesses a Web site within a specific time period. See unique user.


Total population of audience being measured.

Unresolved IP addresses

IP addresses that do not identify their 1st or 2nd level domain. Unresolved IP addresses should be aggregated and reported as such. See also domain.


To send data from a computer to a network. An example of uploading data is sending e-mail.

URL(Uniform Resource Locator)

The unique identifying address of any particular page on the Web. It contains all the information required to locate a resource, including its protocol(usually HTTP), server domain name(or IP address), file path(directory and name)and format(usually HTML or CGI).

URL tagging

The process of embedding unique identifiers into URLs contained in HTML content. These identifiers are recognized by Web servers on subsequent browser requests. Identifying visitors through information in the URLs should also allow for an acceptable calculation of visits, if caching is avoided.


Internet bulletin-board application.


An individual with access to the World Wide Web.

User agent string

A field in the server log file which identifies the specific browser software and computer operating system making the request.

User centric measurement

Web audience measurement based on the behavior of a sample of Web users.

User registration

Information contributed by an individual which usually includes characteristics such as the person’s age, gender, zip code and often much more. A site’s registration system is usually based on an ID code or password to allow the site to determine the number of unique visitors and to track a visitor’s behavior within that site.


Person viewing content or ads on the Web. There is currently no way to measure viewers.

Viral marketing

1) Any advertising that propagates itself;
2) Advertising and/or marketing techniques that “spread” like a virus by getting passed on from consumer to consumer and market to market.


Measurement which has been filtered for robotic activity of one or more text and/or graphics downloads from a site without 30 consecutive minutes of inactivity and which can be reasonably attributed to a single browser for a single session. See for ad campaign measurement guidelines.

Visit duration

The length of time the visitor is exposed to a specific ad, Web page or Web site during a single session.


Individual or browser which accesses a Web site within a specific time period.

VRML(Virtual Reality Modeling Language)

Programming language designed to be a 3D analog to HTML.
WAA(Wireless Advertising Association)

Trade association promoting wireless advertising. Members include: hand held device manufacturers, software providers, carriers and operators, agencies, retailers, and advertisers. See for more information.

WAN(Wide Area Network)

A group of computers connected together(a network)which are not located at the same physical location.

WAP(Wireless Application Protocol)

A specification for a set of communication protocols to standardize the way that wireless devices, such as cellular mobile telephones, PDAs and others can be used for Internet-based access.

WAP device

Any device(e.g., mobile phone, PDA, or simulator)that allows access to wireless content.

WAP phones

Mobile phones which utilize wireless application protocol technology to access the Internet. The screen on a WAP phone can be used to deliver ads.

WASP(Wireless Applications Service Provider)

An organization that provides content and applications for wireless devices.

Web beacon

A line of code which is used by a Web site or third party ad server to track a user’s activity, such as a registration or conversion. A Web beacon is often invisible because it is only 1 x 1 pixel in size with no color. Also known as Web bug, 1 by 1 GIF, invisible GIF and tracker GIF.

Web site

The virtual location(domain)for an organization’s or individual’s presence on the World Wide Web.

Web bug

See Web beacon.


Real-time or pre-recorded delivery of a live event’s audio, video, or animation over the Internet.

XML(eXtensible Markup Language)

A richer more dynamic successor to HTML utilizing SGML or HTML type tags to structure information. XLM is used for transferring data and creating applications on the Web. See SGML and HTML.
The percentage of clicks vs. impressions on an ad within a specific page. Also called ad click rate.