Browser – A software program running on a computer that can request, load and display documents available on the Internet. ABCi audits are designed to only count human-initiated browser activity. ABCi audits screen out activity initiated by automated methods.

Census-Based Audit Method – requires direct access to the website’s entire log file. Auditors then work to determine if there is any misleading online activity. Results are typically more consistent than a panel-based or survey method.

Communication Error –the failure of a browser or server to successfully request or transfer a document. ABCi audits only count successful requests or transfers.

Cookie – a uniquely identifying file on the user’s computer. There are two types of cookies: persistent cookies and session cookies. Session cookies are temporary and are erased when the browser exits. Persistent cookies remain on the user’s hard drive until the user erases them or until they expire. Cookies track a user's website activity.

Internal Page Impressions – website activity that is generated by individuals with IP addresses known to be associated with the website such as employees or vendors working on the website. Internal page impression activity is not counted in an ABCi audit.

IP Address –a numerical address assigned to each computer on a network. IP addresses allow computers to be identified by location and activity.

Log file – records all activity on a given website. Log files may collect a variety of data including: date and time stamp, URL served, IP address of requestor, user and more.

Net Deliveries - the newsletters from a given mailing that reached the subscribers email delivery server with a positive status code response received in return. Calculated by subtracting undelivered messages from sent messages.

Page Impressions/Views – the combination of one or more files presented to a viewer as a single document as a result of a single request received by the server. In effect, one request by a valid user should result in one page impression/view being reported. The counted page impression may not necessarily be in focus or visible in the user’s browser.

Panel-Based Audience Measurement – conducted by polling a pre-selected group for information on their usage of the Internet and specific websites. The results are then projected over a larger audience.

Spiders and Robots – programs that run without human intervention. These programs automatically scan and “fetch” data from websites and send that to search engines or other data users. Large search engines use multiple spiders and robots to browse the Internet. Spiders and robots are displayed as unique users or visitors in the website’s log files. Activity generated from identified spiders and robots are not human-generated and are not accounted in an ABCi audit. Our auditors have found that spiders and robots can account for 20 to 25 percent of a website's traffic.

Subscriber (e-newsletter) - the number of unduplicated email addresses that received the edition of the newsletter.

Third-Party Ad Server - a company that specializes in managing, maintaining, serving, tracking, and analyzing the results of online ad campaigns.

Unique Browser - a unique and valid identifier. Sites may use (i) IP+User-Agent and/or (ii) Cookie. This metric measures each browser; it does not measure a person. Counting of unique browsers may overstate or understate the number or individual devices concerned due to factors such as dynamic IP address allocation, significant levels of uniformity in IP and browser combinations operating through a proxy, cookie blocking and deletion.

Unique Users - unduplicated people who have visited the Internet content or advertising during the measurement period. It is the most difficult measure for a census-based measurement organization to report, as the calculation required to reach this metric must include a component that is directly attributable to people, rather than computers or other mechanized devices.

URL (Uniform Resource Locator) – the identifying "address" of any page on the Web (i.e. www.xyz.com). URLs are always unique and contain all the information needed to locate a page.

User Registration – personal information contributed by an individual to a website, such as the visitor’s age, gender, ZIP code, etc. User registration allows a website to determine the number of unique visitors and tracks visitor behavior within the website. Registrations also provide a method of collecting demographic data.

Visit Duration - amount of time between a visitor’s first and last measurable interaction with the site during the course of a single visit. ABCi does not include single page visits in this calculation.

Visits – a series of interactions by a visitor with a site without 30 consecutive minutes of inactivity.

Widgets - are like mini Web pages that reside on a computer desktop or within a Web-based portal or social networking site to provide self-selected entertainment or information. Popular widgets deliver photo albums, music, Web-cam views, games, news, weather, stock updates, calendars and sport statistics, just to name a few.