Microstructure of Collaboration: The Network of Open Source Software

The open source model is a form of software development with source code that is typically made available to all interested parties. At the core of this process is a decentralized production process: open source software development is done by a network of unpaid software developers. Using data from Sourceforge.net, the largest repository of Open Source Software (OSS) projects and contributors on the Internet, we construct two related networks: A Project network and a Contributor network. Knowledge spillovers may be closely related to the structure of such networks, since contributors who work on several projects likely exchange information and knowledge. Defining the number of downloads as output we finds that (i) additional contributors are associated with an increase in output, but that additional contributors to projects in the giant component are associated with greater output gains than additional contributors to projects outside of the giant component; (ii) Betweenness centrality of the project is positively associated with the number of downloads. (iii) Closeness centrality of the project appears also to be positively associated with downloads, but the effect is not statistically significant over all specifications. (iv) Controlling for the correlation between these two measures of centrality (betweenness and closeness), the degree is not positively associated with the number of downloads. (v) The average closeness centrality of the contributors that participated in a project is positively correlated with the success of the project. These results suggest that there are positive spillovers of knowledge for projects occupying critical junctures in the information flow. When we define projects as connected if and only if they had at least two contributors in common, we again find that additional contributors are associated with an increase in output, and again find that this increase is much higher for projects with strong ties than other projects in the giant component

Adware, Shareware, and Consumer Privacy

Programmers can distribute new software to online users either for a fee as shareware or bundle it with advertising banners and distribute it for free as adware. In this paper we study the programmers' choice between these two modes of distribution in the context of a model that take explicit account of the strategic interaction between programmers who develop software, firms that advertise their products through ad banners, and consumers who buy software and consumer products. Adware allows advertisers to send targeted information to specific consumers and may therefore improve their purchasing decisions. At the same time, adware also raises privacy concerns. We study the effect of programmers' choice between shareware and adware on consumers' welfare through its effect on the beneficial information that consumers receive about consumers products on the one hand and their loss of privacy on the other hand. We also examine the implications of improvements in the technology of ad banners and the desirability of bans on the use of adware

The Incentive To Participate In Open Source Projects: A Signaling Approach

This paper examines the incentives of programmers to contribute to open source software projects on a voluntary basis. In particular, the paper looks at this incentive changes as (i) performance becomes more visible to the relevant audience, (ii) effort has a stronger impact on performance, and (iii) performance becomes more informative about talent. In all three cases, it is shown that whether we start from a stable interior equilibrium or an unstable interior equilibrium

IBPP Research Associates: Israel/Lebanon

This article is an interview interview carried out by Mr. Gil Grein--an undergraduate in Embry-Riddle Aeronautical University\u27s Science, Technology, and Globalization program and an IBPP Research Associate--with Dr. Nadav Morag, a lecturer in the Department of Political Science, Tel Aviv University. The two discuss the ramifications of pulling Israeli troops out of southern Lebanon. Conflict participants include: Israeli Defense Forces (IDF), Southern Lebanese Army (SLA), Hezbollah, and United Nations forces

IBPP Research Associates: Israel

The is article is an interview with Dr. Nadav Morag, Department of Political Science, Tel Aviv University, Tel Aviv, Israel 69978, Fax: +972-3-6409515. The interview was carried out by IBPP research associate Gil Grein, and it focused on United States Vice Presidential Candidate Joseph Lieberman\u27s religious affiliation with Orthodox Judaism

Is Oprah Contagious? Identifying Demand Spillovers in Product Networks

We study the online contagion of exogenous demand shocks generated by book reviews featured on the Oprah Winfrey TV show and published in the New York Times, through the co-purchase recommendation network on Amazon.com. These exogenous events may ripple through and affect the demand for a 'network' of related books that were not explicitly mentioned in a review but were located 'close' to reviewed books in this network. Using a difference-in-differences matched-sample approach, we identify the extent of the variations caused by the visibility of the online network and distinguish this effect from variation caused by hidden product complementarities. Our results show that the demand shock diffuses to books that are upto five links away from the reviewed book, and that this diffused shock persists for a substantial number of days, although the depth and the magnitude of diffusion varies widely across books at the same network distance from the focal product. We then analyze how product characteristics, assortative mixing and local network structure, play a role in explaining this variation in the depth and persistence of the contagion. Specifically, more clustered local networks 'trap' the diffused demand shocks and cause it to be more intense and of a greater duration but restrict the distance of its spread, while less clustered networks lead to wider contagion of a lower magnitude and duration. Our results provide new evidence of the interplay between a firm's online and offline media strategies and we contribute methods for modeling and analyzing contagion in networks