Computer Terminology/Glossary U-Z

URL (Uniform Resource Locator): The unique address of an Internet resource.

Usability: Level of difficulty of using an online application. Affects response rate and data quality.

Usenet: A distributed conversation system much used as source of aggregated message records for social network analysis.

Vector data: Coordinate-based geographical data. Also see ‘Geographical Information System’ and ‘Raster data’.

Voice Over Internet Protocol (VOIP): Internet telephony (e.g., Skype or Video MSN), later versions of which enable users to communicate via computers with the advantage that they can see as well as hear each other.

Web crawler: Also called a 'Web spider' or 'Web robot'. A program or automated script which browses the World Wide Web in a methodical, automated manner. Many sites, in particular search engines, use this means to provide up to date data. Web crawlers are mostly used to create a copy of all the visited pages for later processing by a search engine that will index the downloaded pages to provide fast searches. Crawlers can also be used to automate maintenance tasks on web sites, such as checking links or validating HTML code. Can also be used to gather specific types of information from Web pages, such as harvesting e-mail addresses. See also 'Spider' and 'Scraper'.

Web log: Information available from Common Logfile Format data and clickstream analysis. See entries for ‘Common Logfile Format’ and ‘Clickstream analysis’.

Webometrics: Measures of online activity, both automated and human, that provide information about online behaviour. Techniques and sources expand in tandem with technological development.

Web Services: A software system designed to support interoperable machine or application-oriented interaction over a network.

Web survey: A social survey conducted over the Web. Also called an 'Internet Survey'.

Web 2.0: A development of the original World Wide Web providing features promoting user participation and support for large scale social networking applications.

Wiki: A computer application enabling incremental contributions by multiple users to elaborate a resource ranging from single documents to encyclopaedias and dictionaries.

Wrapper: Components of middleware systems with which datasets can be Web-enabled or Grid-enabled. They resolve dataset heterogeneity and thus enable integration of different datasets.

XML: ‘Extensible Mark Up Language’.

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