Abstract

The extensive use of the web by many sectors of society has created the potential for new wider impact indicators. This article reviews research about Google Scholar and Google Patents, both of which can be used as sources of impact indicators for academic articles. It also briefly reviews methods to extract types of links and citations from the web as a whole, although the indicators that these generate are now probably too broad and too dominated by automatically generated websites, such as library and publisher catalogues, to be useful in practice. More valuable web-based indicators can be derived from specific types of web pages that cite academic research, such as online presentations, course syllabi, and science blogs. These provide evidence that is easier to understand and use and less likely to be affected by unwanted types of automatically generated content, although they are susceptible to gaming.