Webometrics is a scientific discipline that studies the quantitative aspects of information sources and their use. In other words, webometrics try to measure the World Wide Web, analyses technology usage and provides methods for a simple content analysis. As Figure 1 shows, webometrics is affected by many scientific disciplines:

• Informetrics This scientific discipline uses mathematical and statistical methods to describe and analyse information phenomena and the relationship between them. Informetrics mainly deals with a quantification of the information, measuring of information flows and with the evaluation of information processes. The result of the informetric research may serve for analysis of the quantitative growth of literature, for a measure of the efficiency of information systems, for evaluation of scientific communication, etc.
• Bibliometrics Bibliometrics uses informetric methods like quantitative analysis and data visualisation to determine the characteristics of bibliographic references, citations, authors, institutions, keywords, etc. Bibliometrics further uses citation analysis to clarify the quality of written documents. Bibliometrics as such can be used to evaluate the intensity of the use of librarian and information services.
• Scientometrics Scientometrics is an extension of bibliometrics that is focused on the evaluation of scientific research or individual researchers. The assessment is primarily based on the number and quality of citations of scientific work. Using the scientometric approaches, it is also possible to characterise the historical evolution of scientific communication within a given research field.
• Cybermetrics Cybermetrics includes all previously mentioned disciplines and carries them into the Internet environment. Above all, the Cybermetrics deals with quantitative research of information sources, structures and technologies on the Internet. The subjects of its investigation are all electronic information flows, such as posting in discussion groups, e-mail communication, texting or other forms of communication.

Figure 1: The interrelation of webometrics and bibliometrics, cybermetrics, informetrics and scientometrics.

However, webometrics is primarily based on informetric and bibliometric approaches. The information sources that are studied by webometrics are websites, web pages, parts of web pages, words in web pages, hyperlinks, and web search results. According to a narrow definition, webometrics encompasses five basic categories: web link structure analysis, web page content analysis, web usage analysis, web technology analysis and the evaluation of search engines using informetric methods.

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