1. Goodman et al. [1994] took an early look at Internet diffusion. See Table 11, section IV, for a list of GDI studies and references. Check Wolcott [2001] for new GDI work. 2. Archibugi et al. [1999] and Edquist [1997] provide excellent introductions to the national systems of innovation (NSI) literature. The GDI methodology can also be applied to a region larger than a country or to sub-units within a country, and throughout this paper readers may substitute region for country with no loss of generality. This is in keeping with similar extensions to the NSI approach [Howells 1999]. We return to the NSI approach in section III. 3. A much more complete map of the information industries is provided by Houghton [1999], who defines 16 segments divided on the horizontal axis by conduits to content (form to substance), and on the vertical axis by products to services. 4. When data are available to do so, we exclude those who have only UUCP, Fido, or any store and forward accounts. 5. Health, commercial, and academic were initially selected because they corresponded to categories in the United Nations Development Programme (UNDP) human development index. The public sector is obviously a very important user, potentially comparable in size to the others. Seehttp://www.undp.org/. 6. For each network, they derive the cyclomatic number and the alpha, beta, and gamma, which are all ratios derived using various formulas from the number of nodes and connections between nodes (edges) in a graph. This is the underlying structure that comprises a computer network. Gorman and Malecki [2000, pg. 120] provide more precise definitions. 7. Van Slyke [1998] traces the concept of technology clusters to Silverman and Baily [1961], whereas LaRose and Hoag [1996] cite Rogers [1986] as the primary source. Technology clusters in information technology have been examined for a least a decade [cf. Chin and Moore 1991]. King et al. [1994] discuss clusters in the broader context of institutions and their role in innovation diffusion. Prescott and Van Slyke [1997] recommended treating the Internet as a cluster and summarize some evidence in support of this approach. Hahn and Schoch [1997] emphasize that a cluster entails adoption of some, but not necessarily all, of the constituent technologies. 8. Institutional views have been taken by Daly [1999] and the "Internet Counts" project with which he has been affiliated [Wilson et al. 1998]. The Leland Initiative Telematics for Africa project at the Center for International Development and Conflict Management (CIDCM) at the University of Maryland is developing an instrument for Internet assessment that is highly focused on institutions and uses qualitative data gathering techniques [bridges.org 2001]. 9. The GDI work grew out of a similar approach to measuring the information systems capability of a nation, developed by Wolcott et al. [1996]. Sharif [1988] provided an important example of technology assessment measurement, and Liff et al. [1993] provided an important example of devising dimensions. It is beyond the scope of this paper to formulate an overarching theory of Internet diffusion and to relate it to other general models of Internet diffusion which have already been developed. Daly [2000] has proposed a conceptual framework that interrelates Internet penetration, utilization, and impacts. His model includes many of the same dimensions and determinants as contained in our model. Bazar and Boalch [1997] also put forth a general model of Internet diffusion that has some similarities with our model. Abramson [2000, pg. 70] characterizes our methodology as a "sophisticated adjunct" to "country-by-country Internet user counts," which of course does not capture the full richness of our dimensions and determinants. 10. A somewhat different focus was taken by Basalla [1988], who related evolutionary analogies to the history of technology. The growing field of evolutionary economics represents another application of evolutionary analogies [cf. Nelson and Winter 1982]. 11. Their work differs from ours, however, in that they were trying to characterize information systems themselves. We are trying to find characteristics that reflect the extent of adoption of an innovation (not the innovation per se). In examining properties, functions, and the timing of the introduction of new systems, Ein-Dor and Segev [1993] adopted a combination of phenetic, teleological, and phylogenetic approaches that mirror the traditional methods of evolutionary taxonomy. See Ridley [1986]. 12. An easily accessible summary of his theory may be found in Rogers and Scott [1997]. 13. Larry Press provides a web page with links to many of the Internet measurement efforts. See http://som.csudh.edu/fac/lpress/GDIFF/GDIFFprojects.htm. Hal Varian also maintains a page about Internet metrics at http://www.sims.berkeley.edu/resources/infoecon/Accounting.html. An extensive list of references to all aspects of Internet measurement is maintained by Martin Dodge [2000] at http://www.cybergeography.org (also see Dodge [1998]. 14. Buselle et al. [1999] discuss various approaches to Internet diffusion studies, but all involve adoption as the dependent variable. One typical example of such a study is Teo and Tan [1998]. 15. For example, the IDC/World Times Information Society Index (ISI) aggregates available national-level indicators by category into four measures: computer infrastructure, information infrastructure, Internet infrastructure, and social infrastructure. The social infrastructure consists of "Civil liberties, Newspaper readership per capita, Press freedom, Secondary school enrollment, and Tertiary school enrollment." Sources include IDC, UNESCO, ITU, World Bank, and Freedom House. These are aggregated to form a single index. See World Times/IDC [2000]. This is a good example of a method that does not directly measure Internet diffusion. 16. Sudweeks and Simoff [1999] provide a means for integrating quantitative and qualitative approaches in Internet research that is similar to the GDI methodology. Both ultimately make interpretation central. 17. The GDI methodology has been used by other researchers studying Iran [Adibi et al. 1999] and Uganda [Minges et al. 2000]. Numerous master's level papers have been written as well by various students of some of the authors. 18. Teledatos mainly offered UUCP connections over an X.25, but was upgrading their X.25 backbone in late 1997 so that they could run IP over X.25. 19. Editor's Note: The following reference list contains hyperlinks to World Wide Web pages. Readers with the ability to access the Web directly or are reading the paper on the Web can gain direct access to these linked references. Readers are warned, however, that 1. these links existed as of the date of publication but are not guaranteed to be working thereafter. 2. the contents of Web pages may change over time. Where version information is provided in the References, different versions may not contain the information or the conclusions referenced. 3. the author(s) of the Web pages, not AIS, is (are) responsible for the accuracy of their content. 4. the author(s) of this article, not AIS, is (are) responsible for the accuracy of the URL and version information.