Specialization in the marketplace for ideas.

Organizations that compete for attention in the marketplace face a strategic decision: whether to target a specialized niche or diversify to reach a broader market. Previous research has extensively analyzed the specialization dilemma faced by for-profit firms. We extend the analysis to knowledge-sharing groups in the marketplace of ideas. Using data on over 1,500 technology groups collected from an online event-organizing platform over a fifteen-year period, we measure the effect of topical focus, rarity, novelty, and technical exclusivity on audience growth, retention, and sustained engagement. We find that knowledge-sharing groups benefit marginally by specializing in rare topics but not in new topics. The strongest predictor of growth and survival is whether the group is associated with technically sophisticated topics, regardless of the breadth of focus, even though technical topics are less widely accessible. We conclude that what matters is not how specialized the organization, but how the organization is specialized.

A theory of emergence: Knowledge, rewiring and innovation.

Why do social interactions linked to sharing knowledge drive the emergence of a regional technology economy? We proffer a positive theory and explanation-sketch identifying mechanisms and initial conditions in an explanation of emergence of a knowledge economy. We trace the emergence of a knowledge economy, from a small group of founding members to a regional technology economy. With the rapid influx of new people, knowledge spillover motivates technologists and entrepreneurs to reach out beyond existing contacts to explore the expanding knowledge economy and interact with new acquaintances in the search for novelty. In the course of network rewiring in knowledge clusters, individuals share knowledge and cooperate in innovation, and move to more central positions when they interact. Mirroring the trends of increased knowledge exploration and innovative activity at the individual level, new startup firms founded during this time period come to span a greater number of industry groups. Endogenous dynamics of overlapping knowledge networks lie behind the rapid morphogenesis of new regional technology economies in New York City and Los Angeles.

Emergence of diverse and specialized knowledge in a metropolitan tech cluster.

Specialized knowledge is increasingly central in modern information- and technology-oriented economies, yet we know surprisingly little about how this knowledge is organized. We trace the evolution of specialized knowledge at both the individual- and network-levels by analyzing email exchanges shared among members of a large tech professional community in New York City over seven years. We find a shift over time toward the emergence of an increasingly specialized ecology of knowledge and information. This division of knowledge is driven by the influx of new cohorts of participants with different knowledge and interests than those already there. Yet, even as individual contributors increasingly sort into specialized niches, the community as a whole remains robust in its ability to address topics of diverse concern. This study illustrates how new sources of data enable us to see with greater clarity the structures underpinning modern knowledge-based innovation clusters.

Homophily in the career mobility of China's political elite.

We argue that leadership promotion in China's political elite relies on homophily for signals of trustworthiness and future cooperative behavior more than on economic performance. We first point to the limitation of the economic performance argument from within the framework of China's specific M-form state structure, and then we proffer a sociological explanation for why higher-level elites in China rely on homophilous associations in recruiting middle-level elites to the top positions of state. Using a unique dataset covering China's provincial leaders from 1979 to 2011, we develop a homophily index focusing on joint origin, joint education and joint work experience. We trace personal similarities in these respects between provincial leaders and members of China's supreme decision-making body, the Politbureau's Standing Committee. We then provide robust evidence confirming the persisting impact of homophilous associations on promotion patterns in post-reform China.