Information cascades are phenomena in which individuals adopt a new action or idea due to influence by others. As such a process spreads through an underlying social network, it can result in widespread adoption overall. We consider information cascades in the context of recommendations, and in particular study the patterns of cascading recommendations that arise in large social networks. We investigate a large person-to-person recommendation network, consisting of four million people who made sixteen million recommendations on half a million products. Such a dataset allows us to pose a number of fundamental questions: What kinds of cascades arise frequently in real life? What features distinguish them? We enumerate and count cascade subgraphs on large directed graphs; as one component of this, we develop a novel efficient heuristic based on graph isomorphism testing that scales to large datasets. We discover novel patterns: the distribution of cascade sizes is approximately heavy-tailed; cascades tend to be shallow, but occasional large bursts of propagation can occur. The relative abundance of di#erent cascade subgraphs suggests subtle properties of the underlying social network and recommendation process.

Despite the existence of many security schemes for BGP with varying properties, to date there has been little progress on actual BGP security adoption. Although feasibility for widespread adoption remains the greatest hurdle for BGP security, there has been little quantitative research into what exactly improves the adoptability of a security scheme. To the best of our knowledge, we provide the first model for characterizing the adoptability of a protocol. Furthermore, we present an approach for performing this evaluation by simulating incentives compatible adoption decisions of ISPs on the Internet under a variety of assumptions. Our extensive evaluation results include: (a) the existence of a sharp threshold, where, if the cost of adoption is below the threshold, complete adoption takes place, while almost no adoption takes place above the threshold; (b) under a strong attacker model, adding a single hop of path authentication to origin authentication yields similar adoptability characteristics as a full path security scheme; (c) under a weaker attacker model, adding full path authentication (e.g., via S-BGP [10]) significantly improves the adoptability of BGP security over weaker path security schemes such as soBGP [18]. These results provide insight into the development of more adoptable secure BGP protocols and demonstrate the importance of studying adoptability of protocols. 1

Research in organizational learning has demonstrated processes and occasionally performance implications of acquisition of declarative (know-what) and procedural (know-how) knowledge. However, considerably less attention has been paid to learned characteristics of relationships that affect the decision to seek information from other people. Based on a review of the social network, information processing, and organizational learning literatures, along with the results of a previous qualitative study, we propose a formal model of information seeking in which the probability of seeking information from another person is a function of (1) knowing what that person knows; (2) valuing what that person knows; (3) being able to gain timely access to that person’s thinking; and (4) perceiving that seeking information from that person would not be too costly. We also hypothesize that the knowing, access, and cost variables mediate the relationship between physical proximity and information seeking. The model is tested using two separate research sites to provide replication. The results indicate strong support for the model and the mediation hypothesis (with the exception of the cost variable). Implications are drawn for the study of both transactive memory and organizational learning, as well as for management practice.

the company level has been dominated by what goes on inside companies. Thinking about the competitiveness of nations and states has focused on the economy as a whole, with national economic policy seen as the dominant influence. In both competition and competitiveness the role of location is all but absent. If anything, the tendency has been to see location as diminishing in importance. 1 Globalization allows companies to source capital, goods, and technology from anywhere and to locate operations wherever it is most cost effective. Governments are widely seen as losing their influence over competition to global forces. This perspective, although widespread, does not accord with competitive reality. In The Competitive

Even though the literature on the adoption and use of mobile services is quite extensive, surprisingly few studies are found applying traditional models of ICT adoption such as the technology acceptance model. This suggests different perspectives are applied in studies of mobile ICT adoption and traditional ICT adoption. With the introduction of 3G services, a convergence of mobile services and traditional Internet services is expected. Thus, traditional models of ICT adoption may be applied improving our understanding of the adoption of these services. However, studies of the use and adoption of mobile services indicate that traditional adoption models need to be extended and modified when applied to mobile services. In this study, we apply a modified version of the decomposed theory of planned behavior to the adoption behavior of early adopters of mobile commerce services. The study shows that the extended and modified model has good fit to the early adopter data, and that it explains 49 percent of the early adopters' intentions to use mobile commerce services. The model may be used as a basis for industry players' evaluation of the adoption potential of new mobile services.

The threat of climate change, potentially produced by the growing accumulation of greenhouse gases (GHG) in the atmosphere, has led to an increasing number of empirical models for climate change policy analysis. Numerous modeling studies have shown the sensitivity of midand long-run climate change mitigation cost and benefit projections to assumptions about technology. Technological change is in general considered to be a non-economic, exogenous variable in energy-economy models. Economic activities and policies have then no impact on research, development, and diffusion of new technologies. However, there is overwhelming evidence that technological change is not an exogenous variable, but to an important degree endogenous, induced by needs and pressures. Hence, a new generation of environmental-economic models treats technological change as endogenous, i.e. responding to socioeconomic (policy) variables, e.g. prices, investment in R&D, or cumulative production.

We explore how interorganizational networks coevolve with technology in the modern flight simulation industry. Since industries characterized by complex technologies, like flight simulation, rely on cooperative groups such as technical committees, task forces, and standards bodies to adjudicate the process of technological evolution, we focus on these groups and term them “cooperative technical organizations ” (CTOs). Focusing on CTOs enables a multi-level examination of interorganizational networks, as individuals represent their employing organizations in CTOs, mapping into overlapping membership patterns which generate community-wide networks. We develop a set of propositions on the emergence, growth and re-formation of CTO networks, and explore how the evolution of these networks both shapes and is constrained by technological outcomes in the flight simulation industry. We argue that varying levels of technological uncertainty between eras of ferment (high uncertainty) and eras of incremental change (low uncertainty) engender fundamentally different modes of network evolution: social construction during eras of ferment, and technological determinism during eras of incremental

Local policy adoptions provide an excellent opportunity to test among potential mechanisms of policy diffusion. By examining three types of antismoking policy choices by the 675 largest U.S. cities between 1975 and 2000, we uncover robust patterns of policy diffusion, yielding three key findings. First, we distinguish among and find evidence for four mechanisms of policy diffusion: learning from earlier adopters, economic competition among proximate cities, imitation of larger cities, and coercion by state governments. Second, we find a temporal component to these effects, with imitation being a more short-lived diffusion process than the others. Third, we show that these mechanisms are conditional, with larger cities being better able to learn from others, less fearful of economic spillovers, and less likely to rely on imitation. The promise of state and local policymaking in a federal system is that these subnational governments may serve as laboratories of democracy, where they experiment with different policies and learn from one another. The peril is that each government may advance its own interests at the expense of others, leading to the possibility of destructive competition and coercion. Scholars of federalism and intergovernmental relations

Working papers are in draft form. This working paper is distributed for purposes of comment and discussion only. It may not be reproduced without the permission of the copyright holder. Copies of working papers are available from the authors. Explaining the Size of the Mutual Fund Industry Around the World* This paper studies the mutual fund industry in 56 countries and tests various hypotheses to explain the extent to which this innovative form of financial intermediation has flourished. Consistent with related findings from the law and economics literature, the mutual fund industry is larger in countries with stronger rules, laws, and regulations, specifically where mutual fund investors ’ rights are better protected. The industry is smaller in countries where barriers to entry are higher, measured by the effort required to set up a new fund. The fund industry is larger in countries with a wealthier and more educated population, and where the industry itself is older. Finally, the fund industry is larger in countries in which defined contribution pension plans are more prevalent. These results indicate that laws and regulation, supply-side, and demand-side factors simultaneously affect the size of the mutual fund industry. These factors are also related to the recent growth rates of the fund industry across

One of the recent phenomena information systems (IS) practitioners are currently facing in their continuous process of adopting new technology is the utilization of Extensible Markup Language (XML). In this paper we propose an XML adoption framework, a corresponding adoption space model, and a probit model of technology diffusion to examine the decision of adopting XML-based applications in the context of electronic business. First, an XML adoption framework is proposed. The framework helps companies examine their current status in the electronic business environment from the perspective of three electronic business domains, namely enterprise intranets, value-chain extranets, and the global Internet. This framework also provides guidelines for companies seeking to understand the potential benefits of adopting XML technology, and then further suggests the appropriate path and proper applications. Second, we propose an XML adoption space model. Considering its current status of IT applications, a company can utilize this model to measure the efforts/costs that will be incurred by developing XML-enabled IT applications. Third, we use a probit model of technology diffusion to explore the feasibility of a company's adoption of XML technology. This probit model considers a company's specific characteristics and evaluates benefits and efforts/costs of its XML adoption decision. Keywords: E-Business, Decision Model, Framework, XML 1.